PELLETED

DRY RA TIO N S VERSUS STANDARD M E A T RATIONS
FOR

TROUT

By
EDWARD F . GRASSL

C o p y r i g h t by
Edward F . G r a s s l
1956

A THESIS
S u b m i t t e d t o t h e S c h o o l of A d v a n c e d G r a d u a t e S t u d i e s of
M i c h i g a n S t a t e U n i v e r s i t y of A g r i c u l t u r e a n d A p p l i e d
S c i e n c e i n p a r t i a l f u l f i l l m e n t of t h e r e q u i r e m e n t s
f o r t h e d e g r e e of

DOCTOR OF

PHILOSOPHY

D e p a r t m e n t of P o u l t r y H u s b a n d r y
and
I n s t i t u t e of N u t r i t i o n

1956

ProQuest Number: 10008673

All rights reserved
INFORMATION TO ALL USERS
The quality of this reproduction is dependent upon the quality of the copy submitted.
In the unlikely event that the author did not send a complete manuscript
and there are missing pages, these will be noted. Also, if materia! had to be removed,
a note will indicate the deletion.

uest,
ProQuest 10008673
Published by ProQuest LLC (2016). Copyright of the Dissertation is held by the Author.
All rights reserved.
This work is protected against unauthorized copying under Title 17, United States Code
Microform Edition © ProQuest LLC.

ProQuest LLC.
789 East Eisenhower Parkway
P.O. Box 1346
Ann Arbor, Ml 4 8 1 0 6 - 1346

ABSTRACT

D iets
to c o m p a r e

consisting

of a n i m a l a n d v e g e t a b l e m e a l s

w ere

d r y m e a l d i e t s to c h o p p e d r a w m e a t m i x t u r e s

to r a i n b o w a n d b r o o k t r o u t .

pelleted

when fed

E v a l u a t i o n of t h e p e r f o r m a n c e

d iet was b a se d on data gained f ro m feeding la rg e n u m b e rs

of e a c h
of t r o u t .

B im o n th ly w eight and le n g th m e a s u r e m e n t s , daily l o s s e s , and p h y s i­
o l o g i c a l c h a n g e s w e r e u s e d to d e t e r m i n e

t h e n u t r i t i o n a l v a l u e of

e a c h diet.
P e ll e te d d r y - m e a l d ie ts w e re not im m e d ia te ly a c c e p te d a s food
by rainbow and b ro o k trout.

This

was

e v i d e n c e d by a l o s s

d u r i n g t h e f i r s t t w o w e e k s of f e e d i n g p e l l e t e d f o o d .
com pletely

regained afte r four weeks

L o s t w eight w as

of f e e d i n g .

A ll d r y - m e a l d ie t i n g r e d i e n t s in the c o m b in a ti o n s
acceptable as

used w ere

tr o u t food w h en s u p p le m e n te d w ith r a w b eef l i v e r a t

l e a s t one day e v e ry th r e e

weeks.

The dry diets

can be fed a t lev els

o n e - h a lf to f iv e - e ig h th s lo w e r th a n th o s e r e c o m m e n d e d f o r
m ix tu res

of w e i g h t

w ithout re d u c in g

tro u t grow th ra te s .

The d iffe re n c e b e tw e e n a d ie t containing to ru la
one containing b r e w e r s

raw -m eat

yeast was

statistically

y east and

significant when ev a l­

u a t e d b y p e r c e n t g a i n i n w e i g h t of r a i n b o w t r o u t .

A lso , it w as

shown

g r a p h i c a l l y a n d s t a t i s t i c a l l y t h a t o n e d r y p e l l e t e d d i e t ( D i e t 2) w a s
superior

to a r a w b e e f l i v e r

diet.

F e e d i n g the d r y d ie ts d e s c r i b e d did not c a u s e a r e d u c t io n in
num bers
thought.

of r e d b l o o d c e l l s

per

m i l l i m e t e r of b l o o d a s w a s o r i g i n a l l y

C ounts w e re a s high an d h ig h e r

than those f r o m

a n d b r o o k tr o u t fe d a n a l l- b e e f li v e r diet.

rainbow

Even a fte r feeding dry

d i e t s f o r tw e lv e m o n t h s w ith o u t r a w m e a t s u p p l e m e n t a t i o n no n u t r i ­
tional a n e m ia w as

evident.

F is h foods in p elle t fo rm
m e a t diets f o r a d m in is te rin g

offer

m edicam ents

a n d c o n t r o l of b a c t e r i a l d i s e a s e s .

to t r o u t f o r th e p r e v e n t i o n

As d e m o n s t r a t e d by one

m e n t , a n t i b i o t i c s a p p e a r e d to r e l i e v e
furunculosis

sev eral advantages over raw

t h e s e v e r i t y o f a n a t t a c k of

in b ro o k tro u t.

T h e a d o p t i o n of d r y p e l l e t e d d i e t s a s
the

ex p eri­

state fis h h a tc h e rie s

s ta n d a r d r a tio n s by all

i n M i c h i g a n i n c r e a s e d t r o u t p r o d u c t i o n (in

p o u n d s ) b y 60 p e r c e n t a n d r e d u c e d f i s h f o o d e x p e n d i t u r e s b y 4 0 p e r ­
cent.

ii i

ACKNOWLEDGMENTS

T h e a u t h o r w i s h e s to e x p r e s s
S chaible,

com m ittee

c h a ir m a n , fo r his

his

sincere

thanks

to D r . P .

valuable a s s is ta n c e

J.

d u rin g the

p e rio d this w o rk w as u n d erta k en .
H e is a l s o d e e p l y g r a t e f u l to P r o f e s s o r
Z indel fo r allow ing

C a r d a n d D r . H.

C ham pion fo r th e ir valuable help in

sta tistic a l w ork.

G r a t e f u l a c k n o w l e d g m e n t i s a l s o d u e to D r s .
H oppert,

C.

t h i s w o r k to b e c o n d u c t e d i n t h e i r d e p a r t m e n t ;

a n d D r s . W. D. B a t e n a n d L .
conducting

C.

J. L e o n a rd , L. M.

D e p a r tm e n t fo r th e ir helpful

P . I. T a c k , C.

T u rk , an d all the m e m b e r s
suggestions and a s s is ta n c e

of t h e P o u l t r y
in one way

or another.
The w rite r w ishes

to t h a n k D r . L . A l l i s o n w h o

supplied so m e

of t h e b l o o d c o u n t d a t a .
The w r ite r deeply a p p re c ia te s
u s e of th e h a t c h e r y f a c i l i t i e s

the f i n a n c ia l

s u p p o r t a n d the

of th e F i s h D iv is io n , M ic h i g a n D e p a r t ­

m e n t of C o n s e r v a ti o n , an d the In s titu te f o r F i s h e r i e s
to the fo llo w in g m e n in t h e s e

departm ents:

M r.

R e se a rc h , and

M. J . D e B o e r , D r s .

A. S. H a z z a r d a n d G. C o o p e r , a n d M r . F . A. W e s t e r m a n .

A ls o the a u t h o r w is h e s
em ployees
H. H a t t , J .
others

of t h e

state fis h h a tc h e rie s

in M ichigan,

to g a i n d a t a f r o m

scale.

v

experim ents

and

especially M e s srs .

C u r n o w , R. R o b e r t s o n , L . H o o d e m a k e r , J.

who h elp e d m e

p roduction

to t h a n k a l l t h e s u p e r i n t e n d e n t s

S outhw ick, and
conducted on a

Edw ard F. G ra s sl
c a n d i d a t e f o r t h e d e g r e e of
D o c t o r of P h i l o s o p h y

F in a l E xam ination:

D issertatio n :

M a y 4, 1 9 5 6 , 3 : 0 0 p . m . ;
P o u ltr y B uilding.

P e lle te d D ry R ations

V ersus

C onference Room ,

M eat R ations fo r

Trout.

O u t l i n e of S t u d i e s :
M ajor
M inor

subject:
subject:

A nim al nutrition.
B iological c h e m is try .

B io g rap h ical Item s:
Bom,
U ndergraduate

M arshfield, W isconsin,

1919.

Studies:

M ontana State U n iv e rs ity , 1946-1948.
M ic h ig a n State C o lle g e , 1950-1952.
G raduate

S tudies:

M ich ig an State C ollege and U n iv e rs ity ,

1953-1956.

E xperience:
P o u ltr y f a r m m a n a g e r , 1939-1941.
U nited S tates M a rin e C o rp s , 1940-1945.
L a b o ra to ry and production m a n a g e r, P r o c e s s e d T rout Foods,
Inc., 1948-1949.
V ic e -p re s id e n t, P r o c e s s e d T ro u t F o o d s, Inc., 1949-1950.
G r a d u a t e a s s i s t a n t , M ic h ig a n State C o lle g e , 1 9 5 1 -1 9 5 3 .
N u t r i t i o n c o n s u l t a n t , M ic h i g a n D e p a r t m e n t of C o n s e r v a t i o n ,
1953-1956.
M e m b e r of P o u l t r y S c i e n c e , S o c i e t y of S i g m a X i , a n d A m e r i c a n
F i s h e r i e s Society.

vi

TA BLE OF CONTENTS

Page
I N T R O D U C T I O N ...............................................................................................................

1

REV IEW

...................................................................................

6

M e c h a n i c s of F e e d i n g a n d A s s o c i a t e d P r o b l e m s .........................

7

N u t r i e n t s ..........................................................................................................................

8

P r o t e i n .......................................................................................................................

8

F a t ..................................................................................................................................

8

C arbohydrate

........................................................................................................

9

......................................................................................................................

9

V i t a m i n s ...................................................................................................................

10

a n d A n e m i a ..................................................

11

P e l l e t e d F e e d s ............................................................................................................

12

P R E L IM IN A R Y F E E D IN G T R IA L S TO C O M P A R E A
C O M M E R C IA L L Y P E L L E T E D F O O D W ITH A
STA ND A RD HAT CHEF. Y D IE T
...........................................................................

13

FO R M U LA TIO N OF

18

OF LITE R A T U R E

M ineral

Unknown G row th F a c to rs

PELLETED

PRELIM IN A RY FEED IN G

D IET

1
1 .............................

26

L A K E .......................................................................................................................

31

E x p e r i m e n t a l F a c i l i t i e s .......................................................................................

31

D e s c r i p t i o n of E x p e r i m e n t a l E q u i p m e n t ...............................................

32

WOLF

T R I A L S U SI N G D I E T

vii

Page
M e t h o d s a n d P r o c e d u r e f o r A p p l i e d E x p e r i m e n t s ......................

33

E xperim ental R esults

..........................................................................................

40

E V A L U A T I O N O F G R O W T H ...................................................................................

71

C O N D ITIO N F A C T O R O F RAINBOW T R O U T

........................................

73

...............................................

75

R E D B L O O D C E L L C O U N T IN B R O O K A N D R A I N B O W
T R O U T F E D V A R I O U S D I E T S ............................................................................

79

B l o o d S t u d i e s ................................................................................................................

80

D I R E C T AND I N D I R E C T SAVING D U E TO F E E D I N G
P E L L E T E D DRY M EA LS TO H A T C H E R Y -R E A R E D
T R O U T .....................................................................................................................................

85

P O S S IB L E V A L U E OF P E L L E T E D FO O D AS A M ED IUM
F O R D ISPEN SIN G M E D IC A T IO N TO T R O U T
........................................

89

D I S C U S S I O N ..........................................................................................................................

97

BROOK TROUT FEED IN G

EX PER IM EN T

SUM MARY AND CONCLUSIO NS

........................................................................

105

B I B L I O G R A P H Y ................................................................................................................

108

viii

L IST OF T A B L E S

Table
1.

Page
F eed in g tr ia ls co m p arin g p elle te d diets
v e rs u s ra w m e a t diets
............................................................................

16

C o m b i n a t i o n s of f e e d s t u f f s c o m p r e s s e d i n t o
tablet fo rm
................................................ .....................................................

20

R a t e of f a l l a n d d i s i n t e g r a t i o n of t a b l e t s i n
a tu b e of w a t e r e i g h t f e e t h ig h
......................................................

22

4.

P e l l e te d diet c o m p o sitio n

35

5.

P ro x im a te analysis

d i e t s ............................................

36

6.

P e r f o r m a n c e of p e l l e t e d D i e t 1 w h e n f e d
c o n c u r r e n t l y to tw o d i f f e r e n t g r o u p s of
r a i n b o w t r o u t .....................................................................................................

41

P e r f o r m a n c e of v a r i o u s d i e t s d u r i n g a p e r i o d
of t w e n t y - e i g h t w e e k s w h e n f e d to r a i n b o w t r o u t

. . . .

43

T h e r e s u l t s of a s t a t i s t i c a l a n a l y s i s f o r
d if f e r e n c e s in the p e r c e n ta g e g ain s in w eight
b e tw e e n g ro u p s fe d p e lle te d diets and a ra w
beef liv e r diet and betw een groups fed p elleted
d i e t s ..........................................................................................................................

60

C o m p a r i s o n o f n u m b e r a n d w e i g h t of l e g a l a n d
s u b l e g a l - s i z e d tr o u t in g r o u p s r e c e iv in g five
d iffere n t p e llete d d iets and one m e a t diet
.........................

62

C o m p a r i s o n of p e r c e n t a g e of l e g a l a n d s u b l e g a l
ra in b o w tr o u t fe d five d iffe re n t p e lle te d diets
an d one m e a t d ie t
.......................................................................................

63

2.

3.

7.

8.

9.

10 .

.....................................................................

of v a r i o u s

ix

T a b le
11 .

12.

13.

1-4.

15.

Page
A v e r a g e w e i g h t a n d l e n g t h of r a i n b o w t r o u t
f e d v a r i o u s d i e t s a t t h e s t a r t a n d e n d of a
six-m onth period
..........................................................................................

66

N u m b e r a n d a v e r a g e l e n g t h of s o r t e d r a i n b o w
t r o u t a t t h e e n d of a s i x - m o n t h e x p e r i m e n t a l
p e r i o d .......................................................................................................................

67

C o n d itio n f a c t o r of r a i n b o w t r o u t f e d fiv e
d i f f e r e n t d i e t s o v e r a p e r i o d of t w e n t y - f o u r
w e e k s .......................................................................................................................

69

C o n d i t i o n f a c t o r of t h r e e s i z e g r o u p s of
rain b o w tro u t fed various diets
......................................................

70

D iet 1 w hen s u p p le m e n te d w ith
one day e v e r y w eek, one day e v e ry
one day e v e ry th r e e w e e k s, using
t e s t a n i m a l s .................................................................

77

16 .

S u m m a r y of b r o o k t r o u t g r o w t h e x p e r i m e n t s ........................

78

17.

N u m b e r of r e d b lo o d c e l l s p e r c u b ic m i l l i m e t e r
of b l o o d i n b r o o k t r o u t ............................................................................

81

N u m b e r of r e d b l o o d c e l l s p e r c u b i c m i l l i m e t e r
of b l o o d i n r a i n b o w t r o u t
....................................................................

82

N u m b e r of r e d b l o o d c e l l s p e r c u b i c m i l l i m e t e r
................................................................................................................
of b lo o d

84

T h e f i n a n c i a l s t o r y o f f i s h f u n d i n r e l a t i o n to
t r o u t p r o d u c t i o n .............................................................................................

86

P r o d u c t i o n c o s t s a s c o m p a r e d to t h e o l d a n d
new tro u t feeding re g im e
....................................................................

87

F u n c t i o n of a u r e o m y c i n i n b r o o k t r o u t d i e t s

95

18.

19.

20.

21.

22.

P e r f o r m a n c e of
raw beef liv er
two w e e k s , a n d
brook trout as

x

.......................

LIST OF FIGURES

age
L o s s a n d g a i n i n w e i g h t of r a i n b o w t r o u t f e d
t h e s a m e d i e t p e l l e t e d i n t h r e e s i z e s ..............

28

G r o w t h of t w o g r o u p s of r a i n b o w t r o u t f e d
D i e t 1 .............................................................................................

46

C o m p a r i s o n of g r o w t h r a t e s of r a i n b o w t r o u t
.............................................................
fed d ifferent diets

49

C o m p a r i s o n of g r o w t h r a t e s of r a i n b o w t r o u t
fed different diets
.............................................................

50

C o m p a r i s o n of g r o w t h r a t e s of r a i n b o w t r o u t
fed d ifferent diets
.............................................................

51

C o m p a r i s o n of g r o w t h r a t e s o f r a i n b o w t r o u t
fed different diets
.............................................................

52

C o m p a r i s o n of g r o w t h r a t e s of r a i n b o w t r o u t
.............................................................
fed different diets

53

C o m p a r i s o n of g r o w t h r a t e s o f r a i n b o w t r o u t
fed d ifferent diets
.............................................................

54

C o m p a r i s o n of g r o w t h r a t e s of r a i n b o w t r o u t
fed d iffere n t diets
.............................................................

55

C o m p a r i s o n of g r o w t h r a t e s of r a i n b o w t r o u t
.............................................................
fed d ifferent diets

56

C o m p a r i s o n of g r o w t h r a t e s of r a i n b o w t r o u t
fed d ifferent diets
.............................................................

57

C o m p a r i s o n of g r o w t h r a t e s of r a i n b o w t r o u t
fed d ifferent diets
.............................................................

58

xi

IN TRO DU CTIO N

T ro u t, like o th e r a n im a ls , d epend on c o m p le x o rg a n ic m a t e ­
rials

a s food.

In th e ir n a tu ra l h ab itat,

other fish larg ely

sm all anim al o rg an ism s

su p p ly the n e c e s s a r y n u t r i e n t s .

t e m p t e d to d o m e s t i c a t e

W hen m a n a t­

tr o u t, one of the m a j o r p r o b l e m s

w a s to

p r o v i d e a d i e t s i m i l a r i n c o m p o s i t i o n to t h a t f o u n d in n a t u r e .
ing

c a rn iv o re s , ra w m e a t products

Be­

w e r e the f i r s t in v e s tig a te d .

ra w a n im a l p ro d u c ts a s beef liv e r, h e a rt, lungs,
w e r e f o u n d to s e r v e a s a r e a s o n a b l e

su b stitu te fo r n a tu ra l food.

d u ctio n r e m a i n e d a t a r e la tiv e ly low le v el,
o t h e r t y p e s of f o o d .

Such

spleen, and fish

S in ce they w e r e a b u n d a n t a n d lo w in c o s t an d as long a s

to i n v e s t i g a t e

and

there

tro u t p ro ­

w as little incentive

The p ractice becam e

so f i r m ly

e s ta b lish e d that even now m any h a tc h e ry tro u t-fe e d fo rm u la tio n s
contain la rg e p ro p o rtio n s
H o w e v e r, during
in fish in g
m ent.

of r a w m e a t p r o d u c t s .

recen t years

com pelled d ra stic

One la r g e

the g r e a t l y i n c r e a s e d i n t e r e s t

ch anges in tro u t cu ltu re and its m a n a g e ­

an d im p o r ta n t ch an g e o c c u r r e d in the M ich ig an

s t a t e p o l i c y of s t o c k i n g l e g a l o r n e a r - l e g a l l e n g t h
t r o u t i n s t e a d of f r y o r f i n g e r l i n g s .
p ro b lem

(seven inches)

The c h a n g e i n t e n s i f i e d the

of f e e d i n g t r o u t in s e v e r a l w a y s .

1

T r o u t k e p t in h a t c h e r i e s

2
for

the lo n g e r tim e

to g r o w t h e m

to l e g a l

size re q u ire d m uch m o re

food, b e tte r b alan ced diets, and m o re la b o r.

Increased

tio n in c o n ju n c tio n w ith a r a p id ly d ev elo p in g
as

w ell a s

the i n c r e a s e d m a n u f a c tu r e

ceutical p u rp o ses
w e n t up a s

created a

shortage

e f f i c i e n t p r o d u c t i o n of h a t c h e r y

c a t an d dog foo d b u s in e s s

of g l a n d e x t r a c t s f o r p h a r m a ­
of m e a t b y - p r o d u c t s .

the d e m a n d g r e w a n d g r a d u a l l y

p r o h i b i t e d t h e u s e of r a w m e a t s

trout p ro d u c­

P rices

re a c h e d a lev el that

a s the s o le d ie t i n g r e d i e n t f o r the
trout.

B e s id e s a v ailab ility and initial p u rc h a s in g c o s ts , d isad v an tag es
a s s o c i a t e d w ith f e e d p r e p a r a t i o n an d s to r a g e
all p ro b le m .

E fficient utilization re q u ire d

units, g r in d e r s ,

s p e c ia l food m ixing

D u rin g thaw ing, p r e l i m i n a r y
w ater-so lu b le nutrients
lines and w e re lo st.
ta in e d only m i n im u m

po o r grow th o r

refrig eratio n

equipm ent, and m u ch la b o r.

to g r i n d i n g a n d m i x i n g ,

s o m e of t h e

e s c a p e d w ith th e exuding liq u id s into w a s te

a m o u n t s o f c e r t a i n n u t r i e n t s , a l l o w i n g no m a r g i n
d em an d in g in d iv id u als, o r n e c e s s ita te d feeding

q u a n t i t i e s p e r u n i t of t i m e

food p ro c e s s in g .

expensive

T h e r e m a i n i n g p o r t i o n of r a w m e a t o f t e n c o n ­

of s a f e t y f o r the m o r e
la rg e r

c o n t r i b u t e d to th e o v e r ­

to o f f s e t t h e n u t r i e n t l o s s

during

In m a n y c a s e s , the l a t t e r f u n c t i o n w a s i g n o r e d a n d
even in c re a s e d m ortality resulted.

D u r i n g a c t u a l fe e d in g o p e r a t i o n s , it w a s d if f i c u lt to h o ld the
d ie t in t a c t w h e n p la c e d in w a t e r .

U su a lly the fin e ly g ro u n d p a r t i c l e s

3
of m e a t f l o a t e d u n e a t e n t h r o u g h t h e p o n d o r r a c e w a y o r
the b o tto m .

F r e q u e n t p o n d c l e a n i n g to p r e v e n t

in c re a s e d lab o r costs.
a t the

pollution

Indigestible connective tissu e a c c u m u la ted

s c r e e n s , w h ic h h a m p e r e d c i r c u l a t i o n a n d r e d u c e d the r a t e

flow n e c e s s a r y fo r

clearing

the w a te r a f te r

T h e i n t e r a c t i o n of t h e s e

disadvantages

of d r y f e e d s i n l i v e s t o c k r a t i o n s

of

each feeding.
c r e a te d in te r e s t in

v eg etab le and a n im a l p ro d u c ts in m e a l f o r m .

the

serious

s e t t l e d to

The w id esp read use

stim ulated in v estig ato rs

to c o m p a r e

e c o n o m i c a l a n d n u t r i t i o n a l v a lu e of d r y f e e d s w ith r a w m e a t s u p ­

p le m e n ts in tr o u t d ie ts .
fine p a r tic le s

T his in t e n s if ie d the p r o b l e m

of f e e d to p r e v e n t a l a r g e l o s s

of b i n d i n g t h e

when p la ced in w ater.

O ne m e th o d w h ich p r o v e d s u c c e s s f u l w as binding g ro u n d b eef
a n d p o r k g la n d s w ith s a l t a n d d r y m e a l s to f o r m
ture.

The d ry m e a ls

a b s o r b e d m u c h of t h e f r e e m e a t j u i c e s

p r e v e n t e d c o n s i d e r a b l e l o s s of b o th .
m eals
and

cost less

sin c e it w as

dent, th e re
raised .

a gelatinous m ix ­

than r a w

Since v e g e ta b le a n d a n i m a l

m e a t p e r u n i t of n u t r i e n t o n a d r y b a s i s

d e m o n s tr a te d that g r e a t e r g ro w th gains

w as a noticeable

w ere

evi­

r e d u c t i o n in th e c o s t p e r p o u n d of f i s h

N e v e r t h e l e s s , high la b o r

grin d in g , and m ixing units

and

costs,

expensive re frig e ra tio n ,

still re m a in e d .

S e v e r a l y e a r s a g o , a c o m m e r c i a l f i s h fo o d in the f o r m

of

*

p e l l e t s a p p e a r e d o n the m a r k e t.

These pellets

w ere m anufactured

4
in the

sizes

3/32

atio n nor m ixing
food.

The p e lle ts

and anim al m eals

x 1/ 8 i n c h a n d 3 / l 6 x 1/ 8

refrig er­

c o n s i s t e d o f f i r m l y p a c k e d p a r t i c l e s of v e g e t a b l e
w hich did not s e p a r a t e

e s s , m o s t of t h e p e l l e t s

was

w ere

th e b o t t o m of the r a c e w a y .

it w as

N either

e q u i p m e n t w a s n e c e s s a r y f o r t h e u t i l i z a t i o n of t h i s

w i t h t h e w a t e r , a n d , if c a r e

dietary

inch.

im m ed iately upon contact

e x e r c i s e d d u rin g the f e e d in g p r o c ­

consum ed before

This

t h e y c o u l d s i n k to

c o n c e n tra te d food p ro v id e d m a n y

e s s e n t i a l s , a n d y e t d ue to u n k n o w n m i s s i n g
still n e c e s s a r y

to f e e d

som e

raw m eat.

dietary fa c to rs,

T h e a d v a n t a g e s of

p e lle te d food o v e r a total r a w m e a t d ie t quickly c r e a t e d i n t e r e s t in
fish c u ltu ral c irc le s , and m any ag en cies began investigating
of p e l l e t e d d r y m e a l s

as

the v a lu e

a s ta n d a r d tr o u t diet.

In M ic h i g a n , i n v e s t i g a t i o n s to d e t e r m i n e

t h e p r a c t i c a b i l i t y of

using p e lle te d d ry fe e d s f o r tr o u t d ie ts b e g a n e a rly in 1952.
s u l t s of th e p r e l i m i n a r y f e e d i n g t e s t s
furth er

e x p e rim e n ta tio n on a w ider
This

practical,
produce

study w as

w ere

Re­

v e ry encouraging and

scale w as b egun in J a n u a ry ,

d i r e c t e d t o w a r d the g o a ls

1953.

of (1) d e v e l o p i n g a

e c o n o m i c a l , p e l l e t e d , d r y m e a l d i e t w h i c h c o u l d b e u s e d to

s tr o n g , h e a lth y , l e g a l - s i z e d tr o u t in the

s h o rte s t tim e possible;

a n d (2) e l i m i n a t i n g t h e n e e d of r a w m e a t .
P re s e n te d in v ario u s p a rts
tions

of t h i s p a p e r a r e

of s e e m i n g l y i n s i g n i f i c a n t e x p e r i m e n t s .

detailed d e s c r ip ­

In s o m e

cases,

solutions

are

o ffe re d w ithout ex actin g

f o rm a tio n is m o re

supporting data.

N evertheless,

t h a n j u s t i f i e d if o n ly one n o v ic e

by c h a n c e , m a y r e a d this

the i n ­

s c ie n t is t who,

t h e s i s i s l e d to u n d e r s t a n d t h a t s o l u t i o n s

m u s t be found f o r m a n y and v a r ie d m in o r p ro b le m s b e fo re a tte m p t­
i n g to s o l v e m a j o r

pro b lem s.

REVIEW O F L IT E R A T U R E

The tech n ical li te r a t u r e
h atcheries

pertaining

is w id e ly d i s p e r s e d - - e s p e c i a ll y the p h a s e s

m in e ra l nutrition.

vances are

F ish

d e a lin g w ith

In E u ro p e , m o s t in f o r m a tio n is found in te c h n ic a l

j o u r n a l s of l i m i t e d c i r c u l a t i o n .

Society,

to n u t r i t i o n of f i s h i n

p u b lis h e d in the

C hem ical A b stra c ts ,

In the U n ited S ta te s ,

scientific a d ­

T r a n s a c t i o n s of t h e A m e r i c a n F i s h e r i e s
vario u s nutrition jo u rn als,

P rogressive

C u ltu rist, and g o v e rn m e n t m im e o g ra p h e d p am p h lets and leaflets.
An extensive

tro u t nutrition before

s u r v e y of o t h e r i n v e s t i g a t o r s i n t h e f i e l d of
193 7 i s p r e s e n t e d i n r e v i e w s b y M c C a y ( 1 9 3 7 a

a n d 19 3 7 b ).
Since
becom e

1937, the i n c r e a s in g

m ore

dem and for h a tc h e ry -b re d fish has

i m p e r a t i v e , w ith the r e s u l t th a t m a n y in v e s tig a tio n s

s t a r t e d to f i n d l a r g e

sources

w ere

of i n e x p e n s i v e a n d n u t r i t i o n a l l y a d e q u a t e

food.
I n o r d e r to d e t e r m i n e

t h e t y p e of f o o d e a t e n b y f i s h , R a n e y

(1941), Id y ll (1942), Ide (1942), C h u r c h i l l (1944), a n d W e lls
stu d ie d the

s to m a c h contents

of w i l d f i s h .

From

th eir w ork it w as

shown th at tro u t eat w hat food is p r e s e n t and available; fo r
plankton, a lg ae,

(1944)

exam ple,

c r u s ta c e a n s , young in s e c ts , p ro to zo a , copepoda, and

7
s m a lle r fish.

H o w e v e r, e v e n though this in f o rm a tio n has b e e n m ad e

available, few in v e stig a to rs
c o n s i s t i n g of s u b s t a n c e s

h a v e u s e d it to f o r m u l a t e a d i e t f o r

trout

w ith a d efin itely k n o w n c o m p o sitio n .

M e c h a n i c s of F e e d i n g a n d A s s o c i a t e d P r o b l e m s

There are

m any v ariables

be c o n tr o lle d in d e te r m in in g
of t h e s e a r e :

(3) t e m p e r a t u r e ;

n u m b e r of f i s h p e r
variables

and M cCay

t h e v a l u e of a d i e t f e d to t r o u t .

(1) t h e a m o u n t a n d m a n n e r of f e e d i n g ;

t e n c y of t h e d i e t ;

These

o th e r th a n diet itse lf w hich m u s t

(4) p H ;

c u b i c f o o t of w a t e r ;

w e r e ably p o in ted out by A g e r s b o rg

(1935a), S tiles and R u s s

and T u n iso n et al.

(2) t h e c o n s i s ­

(5) w a t e r p u r i t y ;

a n d (7) t h e

Some

(6) t h e

s i z e of t h e f i s h .
(1934),

Tunison

(1938), T u n i s o n a n d M c C a y (1935b),

(1944).

T h e a m o u n t of f o o d g i v e n i s d e t e r m i n e d c h i e f l y b y t h e
of f i s h a n d t h e t e m p e r a t u r e

of w a t e r .

Sm all tro u t fe e d on p a r tic le s

s u s p e n d e d in the w a te r , a n d th ey a r e fed often.
an d R o y a l (1929)

H ow ever,

E inarsen

s h o w e d t h a t if t o o m u c h f o o d i s g i v e n t h e r e

e f f i c i e n t u t i l i z a t i o n of f o o d .

size

is in ­

H a g e n (1940), G u ts e ll (1939), D a v is

(1935),

a n d W ilkins-on (1938) b e l i e v e d th a t o v e r f e e d in g w o u ld r e s u l t in s lu g g is h ,
u nh ealth y fis h , and that it is p a r tic u la r ly

e a s y to o v e r f e e d f i s h w h e n

m e a t or fish m e als

som e disag reem en t as

the p r o p e r

tim e

a r e fed.

There

was

t o b e g i n i n c l u s i o n of d r y m e a l s

to

in th e rrfeat d ie t.

Some

w orkers,

from

the

one

of w h o m

Thom pson

tim e f i s h b e g a n to f e e d ,

(1929), b e li e v e d

th a t the f i s h

fore

are

dry

was

m eals

w hereas

should be

incorporated

in the

(1929), u s e d d r y
others,

such as

a t l e a s t two i n c h e s

m eals

D avis
long b e ­

diet.

N utrients

P rotein,

M any in v e stig a to rs

i d e n t i t y a n d a m o u n t of t h e v a r i o u s
(1934) fo u n d t h a t a
e ssary for

show ed that th e re

nutrients

the r a t e

of g r o w t h .

Sekine and K a k iz a k i

u tiliz e d th a n the p r o te i n f r o m

M cCay

(1931)

w a s a g r e a t e r u t i l i z a t i o n of p r o t e i n w i t h d i e t s

fo u n d to a f f e c t its u ti liz a tio n b y f i s h .

F at.

M cCay

th a n 2 5 p e r c e n t p r o t e i n in the d ie t

c o n t a i n i n g t h e l o w e r l e v e l s of p r o t e i n .

T unison e t a l .

n e e d e d by t r o u t .

the

14 p e r c e n t l e v e l of p r o t e i n i n t h e d i e t w a s n e c ­

g ro w th an d that m o r e

did not i n c r e a s e

h a v e a t t e m p t e d to d e t e r m i n e

The

source

of p r o t e i n w a s

A nim al p ro te in was b e tte r

vegetable

sources, as

was

shown by

(1942).

T h e a m o u n t of f a t i n a d i e t p r o d u c e d v a r y i n g

(1937) p o i n t e d o u t t h a t w h e t h e r

a d d e d t o t h e d i e t of t r o u t ,

results.

7 o r 25 p e r c e n t of f a t w a s

80 t o 90 p e r c e n t w a s d i g e s t e d .

M cCay

a n d T u n is o n (1935) b e l ie v e d th a t the l o w e r - m e l t i n g - p o i n t f a t s
oil a n d c o t t o n s e e d oil) w e r e

utilized

(salm on

slightly b e tte r than h y d ro g e n a te d

9
fats

such as

C risco.

H o w ev er, as found by H ess

(1935), f e e d i n g h ig h

l e v e l s of f a t r e s u l t e d i n t h e d e g e n e r a t i o n of t h e p a n c r e a s .
of f i s h f e d d i e t s

containing

high c a rb o h y d ra te

but ordinarily,

10 0 p e r c e n t r a w l i v e r , o r a h i g h f a t o r

content,

C arbohydrate.

showed la rg e

d e p o s its of fa t.

T ro u t utilize c a rb o h y d ra te s

w hen fed d ie ts containing m o r e

w as d e m o n s t r a t e d th a t they d ev elo p ed la r g e
c e n t a g e of g l y c o g e n .
It w a s
because

The liv e rs

to s o m e

t h a n Z0 p e r c e n t , i t

livers

w ith a high p e r ­

T his w as in d ic a te d by M c L a r e n et al.

(1947).

th o u g h t th a t t r o u t c o u ld n o t u tiliz e h ig h l e v e l s of c a r b o h y d r a t e
they have fe w e r is le ts

M ineral.

V ery little

m in e the o p ti m u m

of L a n g e r h a n s

m i n e r a l c o n t e n t of a d i e t .

the w a te r , a n d t h e r e f o r e

than o th er a n im a ls .

w ork has been c a rrie d

d e m o n stra te d by M cC ay e t a l .

o u t to d e t e r ­

N e v e r t h e l e s s , it w as

(1936) th a t f i s h a b s o r b

the n e e d f o r c a l c i u m

calcium fro m

in the d ie t w as c o n ­

t i n g e n t u p o n t h e a m o u n t of c a l c i u m a v a i l a b l e i n t h e w a t e r .
etal

degree,

(1942) a t a l a t e r

date found also that, although f e r r o u s

Tunison
sulphate

w a s to x ic to a n e m i c f i s h , o t h e r i r o n c o m p o u n d s d id n o t a f f e c t t h e m
adversely.

N o n e of t h e i r o n c o m p o u n d s h a d a n y e f f e c t o n n o r m a l

fish.
T itcom b
in a d iet, lo w e r

etal.

(1929)

m ortality

show ed

that w hen ro u g h ag e

r e s u l t e d , b u t the

reaso n s for

was

included

this

effect

10
could not be

established.

O ther te sts by M cCay

c a t e d t h a t w h e n t h e a m o u n t of r o u g h a g e

etal.

(1930) i n d i ­

w as g r e a t e r than 2 4 p e r c e n t

t h e g r o w t h of t r o u t d e c r e a s e d .
F o ster

et a l . (1939),

th a t b u lk a d d e d to a
stall

the

resu ltin g

V itam ins.
ferent

w orking

diet m a y l e s s e n

d eg en eratio n

w ith young
dangers

salm onids,

in d icated

of o v e r f e e d i n g

of t h e p a n c r e a s

and fo re ­

and liv er.

T h e a b i l i t y of t r o u t t o u t i l i z e v i t a m i n s f r o m

dif­

s o u r c e s i s n o t w ell kn o w n , a n d the r e c o g n i t i o n of d e f i c i e n c i e s

a t t r i b u t a b l e t o t h e l a c k of a

specific

v ita m in is often difficult.

A

n u m b e r of a t t e m p t s h a v e b e e n m a d e

to e s t a b l i s h d e f i n i t e v i t a m i n

levels

M cCay and P hillips

r e q u ir e d fo r n o rm a l grow th.

th at tro u t sto re and lo se V itam in A v ery
was a b e tte r

dietary

H e w i t t (1937)

source

slow ly, an d th a t b e e f liv e r

th a n cod li v e r oil o r c a r o te n e .

stated that B and C v itam in s

f i s h t w o to t h r e e y e a r s

(1940) f o u n d

are

n ece ssary for

old.

The re q u ire m e n t for

V ita m in D has not b e e n definitely d e t e r ­

m ined.
The req u irem en ts
m ore

of f i s h f o r B v i t a m i n s h a v e b e e n s t u d i e d

e x te n s iv e ly th a n the r e q u i r e m e n t s f o r the f a t- s o lu b l e v ita m in s .

W orkers

a t th e C o r t l a n d , N e w Y o r k , h a t c h e r y h a v e a t t e m p t e d to e s ­

ta b lis h the r e q u i r e m e n t s

of t h e s e

v itam in s fo r tro u t by feeding v a rio u s

11
am ounts

of t h e v i t a m i n s , a n d a f t e r v a r y i n g p e r i o d s

the o r g a n s

of t r o u t t o d e t e r m i n e m a x i m u m

now ledged th at th e se
vitam ins
fish.

values

w ere

of t i m e a s s a y i n g

storage.

It w as a c k ­

only a p p r o x i m a t e , a n d th a t a ll the

t e s t e d m a y n o t b e n e c e s s a r y f o r t h e p r o d u c t i o n of h e a l t h y

P hillips

et a l . (1947), M c L a r e n et a l . (1947), an d W o lf (1945)

p r e s e n t e d e x c e lle n t data w hich show ed th a t tro u t r e q u ir e

certain B

v ita m in s f o r n o r m a l grow th.

Unknown G row th F a c to r s and A nem ia

In e a r l y in v e s tig a tio n s by M cC ay an d D illey

(1927) a n d M c C a y

(1939), it w a s fo u n d th a t r a w f r e s h m e a t c o n ta in e d a s u b s ta n c e o r
c o m b i n a t i o n of s u b s t a n c e s
d e a t h of t r o u t .

t h e l a c k of w h i c h r e s u l t e d i n a n e m i a a n d

The r e q u ir e d

su b stan ces w ere n ev er iso lated , but

w h en the alc o h o l, a c e to n e , a n d o th e r
to d i e t s

w h i c h of t h e m s e l v e s

grow n (H eard,

1930).

T h e p r e s e n c e of the g r o w t h f a c t o r s

beef, pork, and sheep liv er,

in the

It w a s

have b een

re p o rte d p r e s e n t in

spleen, h e a rt, lungs, k id n ey s, and m e lts

(1931), in s k im m i l k by T u n is o n a n d M c C a y (1933),

eggs, v is c e ra , and possibly c a r c a s s e s

(1935), in f ly m a g g o ts by P h i l l i p s
m osquito la rv a e .

of l i v e r h a d b e e n a d d e d

w ould n o t s u p p o r t g ro w th , th e f i s h h ad

d e m o n s t r a t e d in m a n y a n im a l t i s s u e s .

by M cCay e t a l.

extracts

of s a l m o n b y D o n a l d s o n

et a l . (1940), a n d in m i d g e a n d

12
P elleted F eed s

P u b l i s h e d w o r k o n t h e u s e of p e l l e t e d f e e d s f o r t r o u t i s l i m ­
i t e d to a f e w

scattered

c e r n e d w ith d e s c r ib in g

reports.

B ro c k w a y 's

r e p o r t (1953) w a s c o n ­

the p o t e n t i a l v a lu e of p e l l e t e d t r o u t f o o d s ,

pointing out the a d v a n ta g e s an d d is a d v a n ta g e s

of t h i s t y p e of f o o d

i n r e s p e c t to t h e p e l l e t i n g p r o c e s s a n d t h e p r o b l e m s
w h e n f e d to t r o u t f o r t h e f i r s t t i m e .

encountered

W i l l o u g h b y 's w o r k (1955) w a s

d e s i g n e d to c o m p a r e p e l l e t e d fo o d w ith a r a w m e a t a n d m e a l m i x ­
ture

w h e n f e d to f a i r l y l a r g e b r o w n t r o u t (13.4 p e r p o u n d ).

w o r k a n d p a r t of t h e w o r k r e p o r t e d i n t h i s p a p e r w e r e
a t a p p r o x im a te ly the s a m e

tim e.

The p ro b le m

to t r o u t w a s i n v e s t i g a t e d b y W olf (1953).
s i s t e d of c o l o r i n g p e l l e t s

conducted

of i n t r o d u c i n g p e l l e t s

H is r e p o r t e d w o rk c o n ­

w ith v e g e ta b le d y es

found th at w hen f i r s t fed tro u t p r e f e r r e d

H is

of v a r i o u s

colors.

He

r e d - c o l o r e d p e l l e t s to

g re e n , b lu e , o r yellow .
T h e w o r k r e p o r t e d i n t h i s p a p e r i s , to t h e b e s t o f m y k n o w l ­
edge,

som e

of t h e f i r s t c o n d u c t e d t o s h o w t h e p e r f o r m a n c e of a n o n ­

c o m m e r c i a l p e l l e t e d f o o d w h e n f e d to r a i n b o w a n d b r o o k t r o u t .

pr e l im in a r y

fe e d in g

t r ia l s

to

c o m pa r e

a

C O M M E R C IA L L Y P E L L E T E D FO O D W ITH A
STANDARD H A T C H E R Y DIET

The o b je ctiv e s

of t h e s e

experim ents

w ere

to d e t e r m i n e , a t

a v e r y g e n e r a l l e v e l , t h e v a l u e of p e l l e t e d d r y a n i m a l a n d v e g e t a b l e
m eals

w hen u sed a s food fo r h a t c h e r y - r e a r e d tro u t.

cluded h e re

m erely

in­

to s h o w th e m a n n e r i n w h ic h t r o u t n u t r i t i o n i n ­

v e s tig a tio n evolved in the
specific

They a re

state

q uestions pertaining
I n 195 2 f e e d i n g t r i a l s

of M i c h i g a n r a t h e r t h a n to a n s w e r

to t h e n u t r i t i o n a l r e q u i r e m e n t s
w e r e b e g u n to c o m p a r e

of t r o u t .

the n u t r i tiv e

v a l u e of a c o m m e r c i a l l y p e l l e t e d t r o u t f o o d w i t h o n e of M i c h i g a n ’s
sta n d a rd h a tc h e ry diets.

The ex p erim en ts

O d en State F i s h H atch e ry , O den, M ichigan.
carried

on in o u ts id e , g r a v e l - b o tto m

f l o w of s p r i n g

w ater.

lo n g
w ere

A ll fe ed in g t r i a l s

racew ays

w ere

re c e iv in g a continuous
w ere

not ta k en

the n a t u r a l in c id e n ta l fo o d co n ­

B ro o k tro u t, Salvelinus fontinalis, a p p ro x im a te ly six in ch es

(42 t o 48 g r a m s ) w e r e u s e d f o r t h e t e s t s .
used

fish for

c o n d u c t e d a t the

E x tra precautionary m e a su re s

to p r e v e n t p r e d a t o r y l o s s e s , n o r w a s
tro lled .

w ere

(7,000), no a t t e m p t w as

size uniform ity.

m a d e in e i t h e r g r o u p to s o r t th e

A ll te stin g

on a production scale.

13

Since l a r g e n u m b e r s

w as done by h a tc h e ry p e rso n n e l

14
D iets
the y e a r .
Jane,
ber,

17 a n d

18 w e r e

tested daring

two s e p a r a t e

The f i r s t feeding tr ia l extended f r o m

seasons

Februaxy,

1 9 5 2 , to

1 9 5 2 , a p e r i o d of t w e n t y w e e k s ; a n d t h e s e c o n d , f r o m
1 9 5 2 , to M a y ,

1 9 5 3 , a p e r i o d of t w e n t y - e i g h t w e e k s .

c o n s i s t e d of d r y a n i m a l a n d v e g e t a b l e m e a l s
form .

S ince this

a closed fo rm u la.
of f if t y p a r t s
sta rte r m ash.

N ovem ­

D i e t 17

m a n u f a c t a r e d in p e l le t

w as a c o m m e rc ia l p ro d u c t it w as d is trib u te d
D i e t 18 c o n s i s t e d of a r a w - m e a t m i x t u r e

pork m elts

and fifty p a r ts

of

under

com posed

of a c o m m e r c i a l b a b y c h i c k

T h e l e v e l s of b o t h d i e t s f e d w e r e b a s e d o n t h o s e

re c o m m e n d e d fo r feeding r a w - m e a t m ix tu re s

( D u e l e t a l ., 1 9 4 2 ) .

W h e n f e e d i n g p e l l e t s , m e a t w a s r e c o m m e n d e d o n ce e v e r y two w e e k s
a s a change in diet, alth o u g h it w as p o in te d out by the fe e d m a n u ­
f a c t u r e r that m e a t w as not n e c e s s a r y fo r n o rm a l tro u t grow th and
survival.
w here

At that tim e

an unfortunate

experience a t another hatchery,

the l a t t e r fe e d in g r e c o m m e n d a t i o n w as fo llo w ed , in d ic a te d th a t

ra w m e at was a n e c e ssa ry

s u p p le m e n t fo r th is p e lle te d food.

The

d e ta ils w e r e not a v a ila b le , b u t a n e x t r e m e l y high m o r t a li ty r e s u lt e d .
S ince no o u tw a rd d i s e a s e

sym ptom s

w e re d is c e rn ib le , the high lo s s e s

w e r e a t t r i b u t e d to a d i e t a r y d e f ic ie n c y .
p ellets

w ere used, m e a t was

T h e re a fte r, w henever these

r e c o m m e n d e d to b e f e d o n e d a y p e r

w e e k i n a m o u n t s d o u b l e t h o s e o f t h e d a i l y a l l o w a n c e of p e l l e t s .

15
O n e t e s t of th e a d e q u a c y of a n e x p e r i m e n t i n n u t r i t i o n i s the
a b i l i t y to d u p l i c a t e

resu lts.

w as c a r r i e d o u t a t the

sam e

f o r tw en ty -eig h t w eeks,
as

The

in the f i r s t feed in g tr i a l .

For

this r e a s o n ,

h a tc h e ry fo u r m o n th s la te r and continued
sam e
As

diets and m ethods

shown in T able

e n c e s i n o r g a n i z a t i o n of t h e e x p e r i m e n t w e r e
u s e d , the

the s e c o n d fe e d in g t r i a l

in the n u m b e r s

F rom

the d a ta p r e s e n t e d , the r a t e

of f i s h

experim ent.

1 show s that both d iets p ro d u c e d p o o r r e s u lt s

experim ents.

em ployed

1, t h e o n l y d i f f e r ­

s e a s o n of t h e y e a r , a n d t h e d u r a t i o n of t h e

Table

w ere

in b o th

of g r o w t h a p p e a r s

to b e th e b e s t m e a n s a v a i l a b l e f o r e v a l u a t i n g th e f e e d s t u f f s.
both c a s e s ,

e v e n though g ro w th w as

show ed a g r e a te r

In

slo w , the p e l l e t - f e d g r o u p s

g a in in w e ig h t th a n the m e a t - f e d g r o u p s .

The

f a c t t h a t p e l l e t s p r o d u c e d b e t t e r g a i n s i s p r o b a b l y due to the p h y s i ­
c a l r a t h e r t h a n t h e n u t r i e n t q u a l i t y of e a c h d i e t .

Since fin e ly g ro u n d

r a w m e a t t e n d s to d i s i n t e g r a t e i m m e d i a t e l y upon c o n t a c t w ith w a t e r ,
perhaps

the t r o u t w e r e a b l e to d e r i v e m o r e n u t r i t i v e b e n e f i t f r o m

the p e lle ts

w h i c h r e m a i n e d i n t a c t l o n g e n o u g h to e n a b l e t h e f i s h to

in g e s t the w hole p a r t i c l e .
O t h e r a d v a n t a g e s a t t r i b u t e d to t h e u s e of p e l l e t e d f i s h f o o d ,
how ever, w ere

o b s e r v e d d u r i n g t h i s p e r i o d of e x p e r i m e n t a t i o n .

W hen

a p e l l e t w a s i n g e s t e d b y a f i s h i t r e c e i v e d a l l of t h e n u t r i e n t s

in the

s a m e p r o p o r t i o n s a s w h en the d ie t w a s m a n u fa c tu r e d .

L abor for

16
T able

1.

Feeding t r i a l s co m p arin g pelleted d iets v e r s u s
d ie ts (a v e rag e w a t e r te m p e r a t u r e 46° F .).

Item

F e b r u a r y , 1952
t o J u n e , 1952
D iet

N u m b e r of w e e k s on d i e t . .

17

D iet

18 a

raw m e at

N o v e m b e r , 1952
t o M a y , 1953
D i e t 17

D iet

I8a

20

20

28

28

C o s t p e r 100 p o u n d s of
diet
. ............................. ...

$12.00

$11.00

$13.40

$11.80

C o s t p e r pound of t r o u t
........................................
reared

$ 0.14

$ 0.30

$ 0.56

$ 1.15

M o r ta l ity by f o u r - w e e k
p e r i o d s ( p e t . ) . .........................

3.5

5.5

0.006

0.006

11 .5

6.2

7.2

6.0

1. 13

2.69

4.16

9.99

1. 12

2.45

0.98

1. 9 9

G a i n by f o u r - w e e k p e r i o d s
(pet.)

............................................

C onversion

....................................

A v e r a g e p e r c e n t of b o d y
w eig h t fed p e r day . . . .

cL

S tarter.

50 p e r c e n t p o r k m e l t s ;

50 p e r c e n t c o m m e r c i a l c h ic k

17
food p r e p a r a tio n was re d u c e d b e c a u se
chased.

A lso p ellets

could be

w i t h o u t b e n e f i t of r e f r i g e r a t i o n .

the p e lle ts

s t o r e d f o r r e l a t i v e l y long p e r i o d s
Since m e a t w as fe d only p e r io d i c a l ly ,

la b o r involved in m e a t thaw ing, g rinding,
M ore
gree

com plete

w ere fed as p u r­

et c e te ra , was reduced.

c o n s u m p t i o n of f o o d o c c u r r e d ;

c o n s e q u e n t ly the d e ­

of p o n d p o l l u t i o n w a s l o w e r e d a n d t h e a m o u n t of l a b o r a l l o t t e d

to p o n d - c l e a n i n g

operations

was

reduced.

C o n s i d e r i n g a l l o f t h e a d v a n t a g e s of p e l l e t e d f i s h f o o d o v e r
r a w - m e a t d i e t s , i t w a s d e e m e d a d v i s a b l e to f o r m u l a t e
w h i c h w o u l d l e n d i t s e l f w e l l to t h e p e l l e t i n g p r o c e s s
the

a d ry diet

and fu rn ish

re q u ire d n u trie n ts f o r n o rm al tro u t grow th and survival.
A n id e a l d ie t w ould be one th a t p ro d u c e d re a s o n a b ly ra p id

g r o w th w ith the c h e a p e s t f e e d s tu f f s , a n d y et f u r n i s h the n e c e s s a r y
n u t r i e n t s f o r t h e p r o d u c t i o n of s t r o n g , h a r d y f i s h w h i c h a r e

a b l e to

w i t h s t a n d n a t u r a l c o m p e t i t i o n w h e n s t o c k e d in s t r e a m s a n d l a k e s .

FO R M U LA TIO N OF P E L L E T E D

D IET

1

T h e f o r m u l a t i o n of D i e t 1 w a s b a s e d a s m u c h o n t h e p e l l e t i n g
properties

of t h e d i e t i n g r e d i e n t s a s o n t h e p o t e n t i a l n u t r i t i v e

of t h e f i n i s h e d d i e t .

S ince no d a t a w e r e a v a i l a b l e on the g r o w th -

producing p e rfo rm a n c e
w a s to d e t e r m i n e

of t h i s d i e t w h e n f e d to t r o u t , t h e f i r s t

step

w h i c h c o m b i n a t i o n of d r y m e a l i n g r e d i e n t s k n o w n

to h a v e b e e n u s e d a s r a w - m e a t
tional p ellet.

value

supplem ents

w ould p r o d u c e a f u n c ­

T he d e s i r e d p e lle t w as one w hich d is in te g r a te d

slow ly

o r n o t a t a l l i n w a t e r a n d w h i c h w o u l d f u r n i s h e n o u g h b u o y a n c y to
prev en t rapid

sin k in g to th e b o t t o m

reason, p relim inary

studies

w ere

of a t a n k o r r a c e w a y .

c a r r i e d o u t to d e t e r m i n e w h i c h

in g red ien t co m b in atio n p ro d u ced a c o m p re s s e d m a s s
as

that p e r f o r m e d

d e s i r e d w hen p la c e d in w a te r .
S ince m i n ia t u r e

able, a h an d -o p erated

la b o ra to ry pelleting m a ch in es
Eureka

tablet m achine

aw k w a rd in fu n ctio n and p e rm ittin g
a t a tim e,

c o m p re s s in g an d extruding
use

w ere not a v a il­

was used.

A lthough

t h e p r o d u c t i o n of o n l y o n e t a b l e t

it s e r v e d the in te n d e d p u rp o s e .

On a pro d u ctio n scale,

the

F o r this

s te a m p la y s a n im p o r ta n t ro le in

dry m eals

to f o r m

compact pellets.

of t h e t a b l e t m a c h i n e , i t w a s i m p r a c t i c a l t o u s e

18

In

steam a s

19
a hum idifier.

To c i r c u m v e n t th is p r o b l e m , a

s m a l l a m o u n t of w a t e r

w a s a d d e d to th e m e a l m i x t u r e s a n d c o m p a r a b l e
The diet in g re d ie n ts
and vegetable m e a ls

w ere

selected fro m

resu lts

t h e g r o u p of a n i m a l

k n o w n to p r o d u c e f a v o r a b l e r e s u l t s

to a r a w - m e a t m i x t u r e

to f o r m

w ere attained.

a m u s h - ty p e food.

when added

Skim m ilk ,

b u t t e r m i l k , w hey, c a s e i n , c o t t o n s e e d a n d s o y b e a n oil m e a l s , y e a s t s ,
a n d v a r i o u s t i s s u e a n d g l a n d m e a l s of a n i m a l o r i g i n h a v e b e e n u s e d
s u c c e s s f u lly f o r this p u r p o s e .

Of t h e s e , a g r o u p of p r o d u c t s

selected

f o r th e ir a v a ila b ility in th is a r e a a t n o m in al c o sts, and n u trie n t q u al­
ity a n d q u a n t i ty , w e r e m i x e d in v a r i o u s
Skim m ilk ,

co m b in atio n s and tableted.

co tto n seed m e a l, w heat flo u r m iddlings,

b re w e rs and torula y easts, and fish m eals
tensive inv estig atio n .
s u b j e c t e d to a w a t e r

soybean m eal,

w e r e g iv e n the m o s t e x ­

A fter tableting, each c o m p re s s e d p a rtic le
t e s t em ploying

was

a g la s s tube eig h t f e e t hig h and

two in c h e s in d i a m e t e r f i l l e d w ith w a t e r .

E ach ingredient com bina­

t i o n , a f t e r t a b l e t i n g , w a s p l a c e d i n t o t h e w a t e r a t t h e t o p of t h e t u b e
a n d a l lo w e d to s in k to the b o tt o m .

T h e t i m e r e q u i r e d to s i n k f r o m

th e to p to th e b o t t o m of th e tu b e a n d th e c o n d i t i o n of th e t a b l e t i n
r e s p e c t to d i s i n t e g r a t i o n a t v a r i o u s
used as

criteria
As

in s e le c tin g

distances fro m

the top w e r e

the d ie t c o m b in a tio n .

s h o w n i n T a b l e 2, t w e n t y d i f f e r e n t d i e t c o m b i n a t i o n s w e r e

p r e p a r e d f o r tableting.

Table

3 shows

conditions applied a fte r

stock

20
Table

2.

C o m b i n a t i o n s of f e e d s t u f f s c o m p r e s s e d
pe rcen tag e s ) .

into ta b le t f o r m

(in

C om bination
Ingredient

C ottonseed m e a l
S k i m m i l k .................. . . .
F i s h m e a l ..................
B rew ers
T orula

yeast

yeast

. . .
. . . .

1

2

3

4

5

6

7

8

9

10

22

22

23

23

23

22

22

23

22

23

5

5

5

5

5

5

5

5

5

5

33

33

40

39

39

33

33

40

37

38

5

5

5

5
5

5

5

5

5

5

. . .

...............

2

2

2

2

2

2

2

2

2

2

Condensed fish
..............
soluble s

3

3

3

3

3

3

3

3

10

8

16

21

22

22

22

21

21

22

20

20

Salt io d ized

W heat m id d lin g s

. .

15

M e l t e d b e e f taLlow
G ranulated

gelatin

. . *

N onnutritive fib e r

. . . .

M olasses

. . . .

G round

solution

corncob

...............

7

21

T a b l e 2 (Con tinue d)

C om bination
Ingredient
11

12

13

14

15

16

17

18

19

20

m e a l ...............

25

25

25

22

21

23

23

23

25

23

S k i m m i l k .............................

5

5

5

5

5

5

5

5

5

5

F i s h m e a l .............................

38

38

38

35

33

35

36

38

38

33

......................

5

5

5

5

5

5

5

5

5

5

.........................

2

2

2

2

2

2

2

2

2

2

6

4

3

5

5

20

22

23

20

20

21

22

23

23

22

10

1

2

2

10

10

1

10

8

5

C ottonseed

B rew ers

yeast

T orula yeast
S alt io d ized

..................

Condensed fish
solubles
.................. . .
W h e a t m i d d l i n g s ...............
M elted

beef tallow

G ranulated

gelatin

N onnutritive
M olasses
G round

„ . „
. u .

fiber

. . . .

solution

. . . .

corncob

...............

10
3
1

22
T able

3,

R a te of f a l l and d i s i n t e g r a t i o n of t a b l e t s i n a tu b e of
w a t e r eig h t fe e t high.

Code

C onditions

1

Tim e
to F a l l
8 Feet
(sec.)

a

D epth
Di s i n t e gration
Began
(feet)

C o n d i t i o n of
T a b le t at
8 Feet

0

tallow

separation

2

20 p e t. H z O

38

2.5

com plete d isin teg ratio n

3

20 pet. H O

38

2.5

com plete d isin teg ratio n

4

20 p e t. w a r m

27

0

d isin teg rated
m inute s

Hz °

after 4

5

20 p et. w a r m
H ^O 70° C.

27

0

no d i s i n t e g r a t i o n f o r
10 m i n u t e s

6

10 p e t . w a r m
H O 70° C.

27

0

no d i s i n t e g r a t i o n f o r
10 m i n u t e s

7

no w a te r o r
heat

42

3.0

tallo w

8

20 p e t. H ^O

36

2.5

one-third d isin teg rated

9

--

32

1.5

com plete

10

--

33

1.5

com plete d isin teg ratio n

32

2.0

com plete d isin teg ratio n

33

3.5

tw o -th ird s d isintegrated

32

3.5

one-half d isintegrated

11
12

—

13

separation

d isintegration

13a

1 p e t. H^O
d r i e d 18 h o u r s
a t 70° C .

25

0

no d is in te g r a tio n f o r
6 m inutes

14

1 p e t. H^O
d r i e d 18 h o u r s

25

0

no d i s i n t e g r a t i o n f o r
6 m inute s

w ^

b

at
15

70°

C.

10 p e t . H ^ O

.

.

.

.

23
Table

Code

C onditions

3 (C ontinued)

T im e
to F a l l
8 Feet
(sec.)

D epth
D isinte­
gration
Began

C o n d i t i o n of
T ab let at
8 feet

(feet)

16

10 p e t . H O
d ried 5 m in. at
6 0 ° C.

25

0

disintegrated from
4 to 8 m i n u te s

17

1 pet.
d r i e d 12 h r s .

27

0

d isin teg rated from
2 t o 15 m i n u t e s

18

1 pet.
a ir dried
hrs.

27

0

disin teg rated fro m
2 t o 15 m i n u t e s

12

19

1 p e t, H -,0 a i r
d r i e d 12 h r s .

28

0

disintegrated from
2 to 20 m i n u t e s

20

1 p et. H^O a i r
d r i e d 12 h r s .

0

0

crum bled

a F loated.
Im m ediately.

to to u c h

24
m aterial

was

m ixed, rate

of f a l l t h r o u g h a w a t e r m e d i u m

in s e c o n d s ,

t h e d e p t h a t w h i c h d i s i n t e g r a t i o n of t h e t a b l e t b e g a n , a n d t h e
t i o n of th e t a b l e t a t th e v a r i o u s
tab leted , co rre sp o n d in g
in ch p ellet.

tim e

to a 3 / l 6

The d ifference

intervals.

i n c h , to a

individual p a rtic le s .

The

sm aller

sizes w ere

1 / 8 i n c h , a n d to a 3 / 3 2

in size had little

s o c ia tio n in w a t e r e x c e p t th a t the l a r g e r

Three

condi­

size

effect on ra te

of d i s ­

s e p a r a t e d into m o r e

s iz e did show a slig h tly b e t t e r

su rfa c e glaze.
A ny one of the d ie t c o m b in a tio n s

shown in Table 2, except

1, 7, a n d 2 0 , p r o d u c e d a r e a s o n a b l y s t a b l e p e l l e t .
of m o s t v a lu e g a in e d f r o m
tab lets

this

experim ent re sts

The in fo rm a tio n
in the fa c ts th a t

w h e n n o t su ffic ie n tly d r i e d w ill d i s i n t e g r a t e m o r e q u ic k ly

t h a n d r i e d t a b l e t s , a n d t h a t a s m a l l a m o u n t of m o i s t u r e , p r e f e r a b l y
h e a te d m o i s tu r e , aid ed in p roducing a f i r m e r
a i r - d r i e d than w hen m o is tu re

tablet when oven-

or

w as not added.

To b e g i n w ith, it w as f e l t th a t g r a n u l a t e d g e l a t i n w a s n u t r i ­
tionally u n d e sira b le
vantages

in the d ie t, a n d sin ce d u rin g th e s e te s t s

the a d ­

o v e r th e d i e t s w h i c h c o n t a i n e d no g e l a t i n w e r e n e g l i g i b l e ,

diet c o m b in atio n s 2 th rough 8 w ere

tem porarily

shelved.

D iets

16

to 19, i n c l u s i v e , a f t e r ta b le tin g a n d d r y in g , p r o d u c e d p a r t i c l e s

w hich

a p p e a r e d to b e to o f i r m l y a s s o c i a t e d f o r i n i t i a l p e l l e t f e e d i n g

studies,

25
D iets

15 a n d 2 0 d i s i n t e g r a t e d i m m e d i a t e l y u p o n c o n t a c t w i t h w a t e r

and th erefo re

w ere unsuitable.

It w ill b e noted th a t in D iets
densed fish
creased.

solubles

t h e p e r c e n t of c o n ­

w as d e c r e a s e d , the bin d in g p r o p e r t y w as

in­

A t a 3 p e r c e n t l e v e l a n d a f t e r d r y i n g , d i s i n t e g r a t i o n of

ta b le ts in w a t e r f i r s t b e g a n a t the
In the p e lle tin g p r o c e s s
steam

9 t o 14 , a s

e n d of s i x m i n u t e s .

used by m o st feed m a n u fa c tu re rs,

ap p licatio n and p e lle t drying a r e

two i m p o r t a n t s t e p s .

Since

c o m b i n a t i o n 1 3 a a p p e a r e d to g i v e t h e b e s t l a b o r a t o r y r e s u l t s i n
t h e s e r e s p e c t s it w a s p e l le te d on a p ro d u c tio n s c a le in th r e e
(l/8 ,

3/32, and 3 /l6

feed-m anufacturing

inch in d ia m e te r , and

plant.

A very

d u rin g the p elletin g p r o c e s s ,
no im m e d ia te
a s long a s

in c h long) a t a lo c a l

s m a l l a m o u n t of d u s t i n g o c c u r r e d

W hen p e lle ts w ere p la c e d in w a te r,

d is in t e g r a ti o n took p la c e , an d th ey r e m a i n e d in ta c t f o r

ten m in u tes.

From

the tw enty c o m b in a tio n s

fo r pelleting on a l a r g e r
This

l/4

sizes

tested, n u m b er

13a w a s

selected

sc a le f o r f u r th e r tro u t n u triton studies.

c o m b i n a t i o n w i l l b e r e f e r r e d to h e r e a f t e r a s

D i e t 1.

PR ELIM IN A R Y

T his

FEED IN G

T R IA L S USING D IE T

e x p e r i m e n t w a s d e s i g n e d to (1) c o m p a r e

1

diet p e rfo rm a n c e

o f a n a l l - m e a t d i e t w i t h a n a l l - p e l l e t d i e t w h e n f e d to r a i n b o w t r o u t ,
a n d (2) p r o v i d e t e n t a t i v e i n i t i a l p e l l e t s i z e p r e f e r e n c e
for fu ll-scale

data

h a tc h e r y - tr o u t feeding.

R ainbow tro u t w ere obtained f r o m
B enton H a rb o r, M ichigan, on F e b r u a r y
the H a s tin g s , M ic h ig a n ,

station.

the B e n to n H a r b o r

E i g h t e e n p o u n d s of r a i n b o w t r o u t

p e lle te d D iet 1 and r a w p o rk liv e r.

to f e e d i n g

D iet 1 w as m a n u fa c tu re d by a

c o m m e r c i a l f e e d m a n u f a c tu r e r in M ich ig an
3/3 2 , l / 8 , and 3 /l6

station,

18 , 1 9 5 3 , a n d t r a n s f e r r e d to

w e r e p l a c e d i n e a c h of f o u r c o n c r e t e t a n k s p r e p a r a t o r y

of t h r e e lo ts

essential

in th re e p e llet siz e s:

in c h in d i a m e t e r , a n d l / 4

in c h long.

E a c h one

w a s f e d a d i f f e r e n t s i z e of p e l l e t , a n d t h e f o u r t h , f e d

a ra w p o rk liv e r diet,

serv ed as

a control.

w e r e w eighed an d the data r e c o r d e d .
ducted o v e r a n eig h t-w eek p e rio d .
i n l e n g t h a n d 18 g r a m s

These

experim ents w ere

R ainbow tro u t averaging

in w eight w e re used.

vio u sly b e e n fe d a m e a t diet.

Once a week, all fis h

A ll f is h w e r e

4.5 i n c h e s

These trout had p r e ­
counted b e fo re and

^V alley C ity M illing C om pany, P o r tla n d , M ichigan.

26

con­

27
after

the e ig h t- w e e k p e r io d .

th at died w as r e c o r d e d .
supplem entation.
out d ry -m e a l
than re q u ire d .

T h e l e n g t h a n d w e i g h t of e v e r y f i s h

D iet 1 w as fe d th ro u g h o u t w ithout m e a t

R a w p o r k l i v e r w a s f e d to the

supplem entation.

co n tro l g ro u p w ith­

A ll d ie ts w e r e fe d in a m o u n ts g r e a t e r

At no tim e d u rin g

the

e x p e r i m e n t w a s a l l of t h e f o o d

consum ed.
F igure
the

sam e

liver

1 show s the g ro w th r a te

diet p e lle te d in th re e

diet.

The cu rv es a re

in pounds d e riv e d f r o m

of r a i n b o w t r o u t w h e n f e d

differen t siz e s and when fed a po rk

constructed fro m

w eekly individual gains

d i v i d i n g t h e t o t a l w e i g h t a t t h e e n d of t h e

p e r i o d b y t h e t o t a l n u m b e r of f i s h p r e s e n t i n e a c h g r o u p .
The ra d ic a l change fro m
d ie t was re fle c te d in lo ss
diet.
3 /l6

F ig u re

s o f t m e a t d i e t to a h a r d p e l l e t

of w e i g h t i n t h e g r o u p s f e d t h e p e l l e t e d

1 s h o w s t h a t i t w a s n e c e s s a r y to f e e d t h e

1/ 8 an d

inch p e lle ts fo u r w eeks b efo re lo st w eight w as re g a in e d ,

w h e r e a s o n ly two w e e k s
inch p e lle ts .

was

r e q u i r e d f o r the g r o u p r e c e i v i n g

E v e n th o u g h the

q u ic k ly t h a n th e o t h e r s , the
in w eight a f te r re c o v e ry .
lose

a

l/8

3/32

3/32

inch g ro u p r e c o v e r e d m o r e

inch g ro u p show s a s te a d ie r g a in

T h e g ro u p f e d r a w p o r k l i v e r did not

w e ig h t, a n d g a i n e d w e ig h t s t e a d i ly th ro u g h o u t the

experim ent.

In a n y e x p e r i m e n t a l w o rk , the in v e s t ig a t o r m a y b e c o n fro n te d
w i t h t h e i n a d e q u a c y of t h e d a t a t o a n s w e r

specific

questions.

It is

28

29
f e l t th a t the c u r v e s
that a p a r tic u la r

show n in F ig u r e

1 are

re lia b le but inconclusive

siz e p e lle t w as p r e f e r r e d by fiv e -in c h fish .

It is

s h o w n , h o w e v e r , t h a t a n y o n e of t h e p e l l e t s i z e s

used for

w ill s u p p o r t f i s h life a n d g ro w th f o r

w h e n f e d to t r o u t

a v e ra g in g five in c h e s in length.
w eight p e r

eight w eeks

As d e te r m in e d by lo ss

each group

a n d g a i n of

u n i t of t i m e , r a i n b o w t r o u t s h o u ld b e a l l o w e d a tw o -

f o u r - w e e k a d j u s t m e n t p e r io d w hen changing f r o m

to

a m e a t to a p e l l e t

diet.
I n s u m m a r y of t h e p e l l e t s i z e p r e f e r e n c e

te s ts , it can be

s ta t e d th a t e v en though ra in b o w a n d b ro o k tr o u t a r e
in g estin g la r g e p a r tic le s
rarily

of r e l a t i v e l y

r e l u c t a n t to a c c p t p a r t i c l e s

c a p a b l e of

soft fo o d s, they a r e

tem po­

of n o n r e s i l i e n t f o o d w h i c h a r e

not e a s ily c r u s h e d o r in d e n ted w hen f i r s t m o v e d th ro u g h the b u c c a l
c a v i t y to t h e p h a r y n g e a l a r e a .
pellets

of a n y

size

In o t h e r w o r d s , t e a c h i n g f i s h to e a t

is a v e r y im p o r ta n t fu n c tio n in changing f r o m

a

m e a t to a d r y p e l l e t e d d ie t.
The re su lts

of t h e s e

ex p erim en ts w ere

encouraging

en o u g h to

w a r r a n t f u r t h e r w o r k to d e t e r m i n e w h a t c o m b i n a t i o n of f e e d s t u f f s
a fte r pelleting

w ould f u r n i s h a d e q u a te n u tr i tio n f o r tr o u t w h en fe d

a lo n e a n d in c o m b in a tio n w ith r a w
stoppages and vario u s

m eat.

D u e to f r e q u e n t w a t e r

o th e r conditions a d v e rs e

u s e of th e H a s t i n g s h a t c h e r y f o r th i s p u r p o s e

to e x p e r i m e n t a l w o r k ,
w as discontinued.

New

30
facilities
all

w ere

i n s t a l l e d a t th e W olf L a k e

s u b s e q u e n t e x p e r i m e n t s f o r this a r e a

station.

State F i s h H a tc h e r y , and
w e re c a r r i e d out a t that

W OLF LAKE

E xperim ental F acilities

V

T he follow ing

experim ents

w ere

S tate F i s h H a tc h e r y lo c a te d ten m ile s
The w a te r

c a r r i e d o u t a t the W olf L a k e
w e s t of K a l a m a z o o , M i c h i g a n .

supply f o r the h a tc h e r y c o m e s f r o m

a s p rin g w hich has

a f l o w of a p p r o x i m a t e l y

1500 g a llo n s p e r m in u te .

flo w s into a n o p en a r e a

w hich w as f o r m e d by building a d a m a c r o s s

th e l o w e r e n d of a

sm all valley.

y a r d s l o n g , 30 y a r d s

The c l e a r w a te r

The c r e a te d pond m e a s u r e s

w i d e , a n d 18 f e e t d e e p .

100

The w ater fro m

this

pon d flo w s th r o u g h u n d e r g r o u n d m e ta l p ip e s into the h a t c h e r y b u ild ­
ing.

In th e h a t c h e r y , th e w a t e r t e m p e r a t u r e

F . d u rin g the c o ld e r m o n th s , and f r o m
w arm er

m onths.

v aried fro m

5 0° to 5 8°

42°

F . during

to 50°
the

T h e c o n c e n t r a t i o n of d i s s o l v e d o x y g e n v a r i e d b e ­

tw e e n 6.0 a n d 9.0 p a r t s

p e r m illion.

2.2 p a r t s

T h e p H v a r i e d b e t w e e n 7.5 a n d 8 . 1 , w i t h a n

average

p e r m illion.
p H of 7 . 7 .

C hem ical an aly sis

Free

of t h e w a t e r

o r a n g e a l k a l i n i t y of 1 6 0 p a r t s p e r m i l l i o n .

31

c a r b o n dioxide a v e r a g e d

showed a m ethyl

32
D e s c r i p t i o n of E x p e r i m e n t a l E q u i p m e n t

E leven concrete

tanks and s ix te e n sm all w ooden tro u g h s w e re

c o n s t r u c t e d a t the W olf L a k e
E ach concrete

State F i s h

H atchery

e a r l y in 1953.

t a n k m e a s u r e d 25 x 2 x 3 . 2 5 f e e t .

E a c h of t h e s e

t a n k s w a s d i v i d e d in to two i n d i v i d u a l w a t e r - t i g h t c o m p a r t m e n t s
m easured

11.5 x 2 x 3.25 f e e t .

E ach c o m p a rtm e n t was c o n s tru c te d

to c o n t a i n a n i n d i v id u a l w a t e r i n l e t a n d o u tl e t.
th e c o u r s e of th e

experim ents

c o m p a r t m e n t into the o th e r .

that

A t no t i m e d u r i n g

w a s w a t e r a l l o w e d to flo w f r o m

one

T h e r a t e of f l o w of w a t e r w a s r e g u ­

l a t e d b y tw o 1 - i n c h g a t e - v a l v e s

i n s e r t e d in a 2 - in c h pipe f e e d e r

line.
The six te en w ooden tro u g h s w ere

salvaged fro m

cut-dow n incu­

b a t io n t r o u g h s , the type c o m m o n ly u s e d f o r h a tc h in g t r o u t eg g s.
E a c h finished trough fo r
inches.

One

experim ental use m e a su re d

32 x 6 . 5 x 14

end w as fitte d w ith a 2 - in c h g a lv a n iz e d m e ta l o u tlet

t u b e d i r e c t l y i n f r o n t of w h i c h w a s i n s e r t e d a 6 - m e s h
the o p posite

end w ater

A o n e -fo u rth inch m e s h

co llecto r was placed d irec tly ben eath

screen.

w ere

At

e n te re d th ro u g h a o n e -h a lf inch spigot f r o m

a 2 -in c h f e e d e r pipe line.

troughs

screen.

sc re e n debris

each w a te r in le t spigot.

All

c o m p le te ly c o v e re d by a f r a m e d o n e -fo u rth inch m e s h

F l o w of w a t e r

e n t e r i n g i n d i v i d u a l t r o u g h s w a s r e s t r i c t e d to

eight g allo n s p e r m inute.

The

s o u r c e of w a t e r f o r

tr o u g h s w a s the

33
s a m e a s f o r the ta n k s .
o rg an ism s

entering

N o a t t e m p t w a s m a d e to f i l t e r o u t s m a l l

the h a t c h e r y b u ild in g w ith the w a t e r

supply.

M ethods and P r o c e d u r e fo r A pplied E x p e rim e n ts

T h e a p p l i c a t i o n of s c i e n t i f i c i n v e s t i g a t i o n to p r a c t i c a l f i e l d
use

re q u ire s four p hases

of w o r k .

w i t h t h e d i s c o v e r y of m a j o r f a c t s
of a n i m a l s
resu lts

and sm all am ounts

The f i r s t p h ase is c o n c e rn e d
t h r o u g h t h e u s e of s m a l l n u m b e r s

of m a t e r i a l s ;

ob tain ed on l a r g e r n u m b e rs

a m o u n t s of m a t e r i a l s ;

the

s e c o n d to s e m i p r o d u c t i o n
prom ising

resu lts

instances,

separate

the

second utilizes

of a n i m a l s a n d c o n s i d e r a b l e

third phase applies

the r e s u l t s

of t h e

s c a le ; a n d the f o u r t h p h a s e a p p lie s

of t h e t h i r d to f u l l - s c a l e p r o d u c t i o n .
lab o rato ries a re

the

m aintained for

the

In s o m e

each phase

of

the developm ent.
The

e x p e r i m e n t a l work- a t Wolf L a k e

d e s i g n e d to f o l l o w t h i s

system

e x p e rim e n ta l w ork was

carried

larg e

tanks

inside

g rav el-b o tto m

the building;

racew ays

of p l a n n i n g .
out in s m a ll

on a sem ip ro d u ctio n

full-scale

M arquette;

T h e f i r s t p h a s e of t h e
troughs;

the

s e c o n d , in

the t h i r d , in o u ts id e c o n c r e t e

s t a t i o n s , one the m o s t s o u th e r n , W olf L a k e
m o st north ern ,

State F i s h H a tc h e r y w as

and

s c a l e a t two d i f f e r e n t
H a t c h e r y , a n d one the

a n d fin a lly the r e s u l t s

w ere

s u b j e c t e d to

h a t c h e r y fe e d in g by a ll the M ic h ig a n h a t c h e r i e s .

34
S m all tro u g h s w e re

u sed in each case

an e n tire ly new diet in g red ien t a n d /o r

that r e q u ir e d te stin g

com bination.

T h ree pounds

o f t r o u t w e r e f e d t h e d i e t i n q u e s t i o n f o r a s u f f i c i e n t l e n g t h of t i m e
to d e t e r m i n e

w h eth er fish grow th o c c u rre d .

A fte r it w as d e te r m in e d

th a t the d ie t w a r r a n t e d f u r t h e r in v e s tig a tio n , a m o r e
p e rim e n t was

carried

out in the l a r g e r

o f f i s h w h i c h c o m p a r e d to a
p erim en ts

concrete

sem iproduction

These trout w ere

seven m onths

d i e t u p to t h i s t i m e

and pork

ex­

tanks using n u m b e rs

scale.

F o r these

ex­

12,000 r a in b o w tr o u t , S a lm o g a i r d n e r i , ra n g in g f r o m

to 5 . 9 i n c h e s i n l e n g t h a n d 4 to 2 0 g r a m s ' i n

Their

extensive

s p le e n in v a r i o u s

old a t the

w eight, w e re

s t a r t of t h e

em ployed.

experim ent.

c o n s i s t e d of r a w b e e f a n d s h e e p l i v e r
com binations.

One th o u sa n d w e re p la c e d

i n e a c h of t h e t w e l v e t a n k s p r e v i o u s l y d e s c r i b e d .
included fo u rte e n tw o-w eek p e rio d s,
to A p r i l 2 8 ,

2.9

extending f r o m

The in v e stig a tio n
O ctober

1, 1 9 5 3 ,

1954.

Seven d ifferen t dry a n im a l and vegetable m e al com binations
(Table
there

4) w e r e

c o m p r e s s e d into 3 /3 2

was a ris k

of l o s i n g

d i e t d u e to a lo n g
beginning

of t h e

vestigation.

som e

inch p e lle ts .

E v en though

of t h e n u t r i e n t s p r e s e n t i n e a c h

s t o r a g e p e r i o d , the

s a m e d ie ts p e l l e t e d a t the

e x p e r i m e n t w e r e u s e d f o r t h e d u r a t i o n of t h e i n ­

P r o x i m a t e a n a l y s i s of e a c h d i e t i s r e c o r d e d i n T a b l e

A f t e r the f i s h r e a c h e d a s iz e la r g e

e n o u g h to a c c e p t

5.

1/8 inch p e lle ts

35
T able

4.

P e lle te d d iet com position

(parts).

Diet
C om position
1

2

3

4

5

6

7

38

38

40

40

40

36

36

. . .

23

23

W heat flour
m i d d l i n g s ..................

25

25

Red f is h m e a l

. . . .

C ottonseed m e a l

T orula yeast

...............

B rew ers yeast

23

26

5
5

. . . .

26

25

22

22

5

3

3

3

3

3

3

3

3

3

5

Condensed fish
solubles
. . . . . .

3

3

S k i m m i l k ......................

5

5

5

5

5

5

5

Iodized

2

2

2

2

2

2

2

23

23

25

25

s a l t ..................

S oybean oil m e a l
X anthophyU
G elatin

. .

. . . .

8

0. 2 0

......................

Stabilized fa t
Beef U ver

. . .

. . . . . . .

100

36
Ta.bl,e 5.

P ro x im ate

n a i y s i s of v a r i o u s d i e t s .

D iet

P et.
M oistu re

C rude
P rotein

E ther
Extract

F iber

NFE

Ca

P

A sh

1

8

39.6

5.08

4.70

25.2

3.20

2.10

13.30

z

8

39.3

4.40

4.90

25.3

2.90

2.00

12.80

3

8

40.8

4.23

2.27

27.1

3.34

1.91

13.43

4

8

40.8

4.22

2.27

27.1

3.34

1.91

13.43

5

8

41.9

5.36

4.99

26.3

3.36

2.06

13.80

6

8

41.8

3.84

3.28

25.8

3.05

1.78

12.78

7

8

40.3

5.84

3.28

25.8

3.05

1.78

12.78

8 wet.

7Q

20.2

3.10

0.00

6.0

0.007

0.358

1.3

8 dry

0

66.6

9.99

0.00

19.98

0.023

1.3

4.32

37
all diets

w ere

1/d inch size.

retu rn ed

to t h e f e e d m i l l , c r u s h e d , a n d r e p e l l e t e d to

Then,

s iz e p e l l e t w a s u s e d f o r the r e m a i n i n g

this

ex p erim en tal period.
As
w ere

w a s p o in te d o u t p r e v i o u s l y , the p e r c e n t a g e s

of i n g r e d i e n t s

s e le c te d p r im a r il y fo r th e ir pelleting p r o p e r tie s .

Since it had

b e e n e s t a b l i s h e d th a t D ie t 1 w ould s u p p o rt t r o u t life a ll o th e r d ie ts
w e re b a s e d upon this

com bination.

v ariables

c o t to n s e e d m e a l , s o y b e a n oil m e a l , c o n d e n s e d

fish

w ere

y east,

so lu b le s, xanthophyll,

As

show n in T ab le

sta b iliz e d fat, and gelatin.

a n d 4 w e r e f e d to d u p l i c a t e g r o u p s of f i s h .
raw m e a t control.
variables.

A s is

shown,

4, t h e d i e t

D iets

1, 2, 3,

D ie t 8 s e r v e d a s the

each diet contains one o r m o re

Since the d ie t a s a w hole h a d not b e e n t e s t e d f o r a suf-

f i c i e n t l y lo n g t i m e , the

experim ents

w e r e n o t d e s i g n e d to t e s t th e

v a l u e of a s p e c i f i c

ingredient.

H o w e v e r, a s w ill be p o in te d out

later,

diet

s e v e r a l diet in g re d ie n ts

can be judged w hen g ain in w eight

and m o rtality a re

used as

reason,

w a s p l a c e d o n d u p lic a tio n a n d on d e t e r m i n i n g the

em phasis

c r i t e r i a of d i e t p e r f o r m a n c e .

For

this

p e r f o r m a n c e of d r y p e l l e t e d m e a l d ie ts w h e n s u p p l e m e n t e d p e r i o d i ­
c ally w ith r a w

beef liv e r.

A f t e r p e l l e t i n g , p a r t of e a c h d i e t w a s p l a c e d i n a m e t a l c a n
situated n ear
food.

the g ro u p

The re m a in d e r

of

of f i s h w h ic h w e r e
each diet was

to b e f e d t h e r e s p e c t i v e

s t o r e d in a cool, r e la tiv e ly

38
d ark , d ry place.
body w eight p e r

T h e a m o u n t of f o o d f e d w a s b a s e d o n p e r c e n t of
day, an d all g ro u p s

D iet 1 g ro u p w e re

e x c e p t the m e a t c o n t r o l a n d the

s t a r t e d a t a 3.0 p e r c e n t l e v e l .

Since d e fin ite

fe e d in g l e v e l s h av e n o t b e e n e s t a b l i s h e d f o r p e l l e t e d f o o d s , the
levels

used here a re

to b e c o n s i d e r e d t e n t a t i v e .

The feeding lev els
calculating

the d ry

later.

approxim ations,

e q u i v a l e n t s of t h e l e v e l s

m e a t s by D uel e t a l .
started at a

used are

(1942).

d e t e r m in e d by

suggested fo r raw

B oth m e a t and D iet 1 g ro u p s w e re

4.7 p e r c e n t l e v e l f o r r e a s o n s

w hich a r e

to b e d e s c r i b e d

T h e a m o u n t s of f o o d to b e f e d w e r e d e t e r m i n e d b y u s i n g a

m e t a l c o n t a i n e r m a r k e d a t a le v e l w h ich c o r r e s p o n d e d w ith the d e ­
s i r e d w e i g h t of fo o d f o r e a c h f e e d i n g .
of w e ig h in g m a n y

sm all am ounts

r a w l i v e r w a s d e t e r m i n e d in the
intro d u ced

som e

of the

of p e l l e t s .
sam e

e l i m i n a t e d the n e c e s s i t y
T h e a m o u n t of g r o u n d

m anner.

T h is, no doubt,

e r r o r , b u t the c h a n c e s f o r fe e d in g m o r e th a n the

d e sig n a te d w eighed am o u n t w e re
of fe e d in g l e s s

This

c o n s i d e r e d t o b e e q u a l to t h e c h a n c e s

th a n the d e s ig n a te d am o u n t.

e r r o r was

considered v ery

sm all.

T herefore,

the m a g n itu d e

A l l f i s h w e r e a l l o w e d to

a d j u s t t o t h e p e l l e t e d f o o d f o r a p e r i o d of f o u r w e e k s .

E a c h m orning

b e f o r e fe e d in g o p e r a tio n s b e g a n all ta n k s and troughs w e r e d r a in e d
to a f o u r - i n c h l e v e l a n d th e a c c u m u l a t e d r e f u s e
flow ing down the d ra in .

sw ep t out w ith w a te r

A t this tim e dead tro u t w ere

w eighed,

m e asu re d , and recorded.
cause

A ll t r o u t w e r e

of d e a t h , if p o s s i b l e .

F airb an k s-M o rse
week in terv als.
sufficiently la rg e
w eighed.

scale

the

A 1,000 pound c a p a c ity , p l a t f o r m ,

was

u s e d to w e i g h e a c h l o t of f i s h a t t w o -

A l l f i s h w e r e w e i g h e d b y m e a n s of a c o n t a i n e r
t o h o l d a v o l u m e of w a t e r p l u s t h e f i s h t o b e

T he w a t e r w a s w e ig h e d b e f o r e ad d in g the f i s h , a n d w eig h t

of f i s h w a s d e t e r m i n e d b y d i f f e r e n c e .
fish fro m
and its

e x a m i n e d to d e t e r m i n e

the ta n k e x c e s s

contents.

In e v e r y c a s e a f t e r dipping

w a t e r w a s a l l o w e d to d r a i n f r o m

T h e l e n g t h o f t i m e a l l o t t e d to t h i s

exceed fifteen seconds.

A fter d eterm ining

the n e t

u su ally did not

t h e t o t a l w e i g h t of f i s h

p r e s e n t i n e a c h t a n k , t h e a m o u n t of f o o d i n p e r c e n t o f b o d y w e i g h t
w a s r e c a l c u l a t e d to c o n f o r m
m o r t a li ty the n u m b e r s

to t h e g a i n i n w e i g h t , a n d e x c e p t f o r

of f i s h w e r e h e l d c o n s t a n t .

T h e a m o u n t of

f o o d f e d i n p e r c e n t of b o d y w e i g h t w a s n o t . i n c r e a s e d a f t e r
w eighing p e rio d .

every

It w a s o b s e r v e d t h a t a l l the f o o d w a s n o t e a t e n

a t t h e b e g i n n i n g of t h e
the a m o u n t fe d p e r

experim ent.

H o w e v er, r a t h e r than re d u c e

d ay , th a t is in c a s e s w h e r e the a m o u n t in e x c e s s

w a s n o t t o o g r e a t , t h e t r o u t w e r e a l l o w e d to a d j u s t to t h e p e r c e n t
in body w eight fed by g ro w th in c r e a s e .
sio n f a c t o r s b u t p ro b a b ly a t this tim e ,

This in v a lid a te s

the c o n v e r ­

e stab lish in g a definite feeding

l e v e l w as a s i m p o r t a n t a s gaining a c c u r a t e

conversion fa c to rs.

Since

40
the

tanks

used w ere

g r o w t h , no

adequate in size

" t h i n n i n g 11 w a s

P e lle t feeding

to c o m p e n s a t e f o r i n c r e a s e

in

c a r r i e d out.

schedules

w e r e p l a n n e d to i n c lu d e f o u r p e r i o d s

p e r day f o r fo u r d ay s an d r a w b eef liv e r f o r one day e v e ry w eek.
D u e t o c o n d i t i o n s b e y o n d t h e c o n t r o l of t h e i n v e s t i g a t o r , a l l f o o d
w as w ithheld on S a tu rd a y and Sunday.
received

raw beef liv er

The ra w m e a t control group

e x c lu siv e ly f o r five days a w eek, a n d w ere

a lso fed fo u r tim e s a day.

The usual p ra c tic e

of a d d i n g

w a t e r to

g r o u n d r a w b e e f l i v e r b e f o r e f e e d in g w a s n o t fo llo w e d , the l i v e r
being fed a s it c a m e f r o m
a m o u n t of p a r t i c l e

T h is r e d u c e d the

s e p a ra tio n d u ring feeding.

R eg ressio n analysis,
values acc o rd in g

the m e a t c h o p p e r .

stan d ard e r r o r

t o t h e m e t h o d of S n e d e c o r

of e s t i m a t e , a n d " t "
(1946) w e r e

u s e d to

s t a t i s t i c a l l y a n a l y z e f o r d i f f e r e n c e s in the p e r c e n t g a in in w eig h t
b etw ee n g ro u p s fed p ellete d diets and a ra w beef liv e r diet and
b etw e e n g ro u p s fe d v a rio u s p e lle te d diets.

E x p e rim e n ta l R esults

The re s u lts

of t w e n t y - e i g h t w e e k s of f e e d i n g D i e t 1 a r e p r e ­

se n te d in d e ta il in T able

6.

A ll o th e r d ata f r o m

c lu s i v e , a r e p r e s e n t e d in s u m m a r y only (T able
s u m m a r y of D ie t 1 p e r f o r m a n c e .

The r e s u lts

D i e t s 2 to 8, i n ­

7) a n d i n c l u d e a
of f e e d i n g D i e t 1

41
Table

6.

P e r fo rm a n c e of p ellete d D i e t 1 w hen fed co n cu rren tly to
two d ifferen t grou p s of rainbow tro u t.

F o u r-W eek P eriod
1

3

2

Item
D upli­
cation
11

D upli­
cation
12

D upli­
cation
12

100 0

100 0

9 99

999

997

994

. .

999

999

997

994

996

992

W eight a t end
(pounds)
..................

51.1

51.5

61.6

61.5

75.7

77.0

Weight a t s t a r t
(pounds)
..................

39.6

39.2

51.1

51.5

61.6

61.5

Q ain in w eight

. .

11.5

12.3

10. 5

10.0

14.2

15.5

C o s t p e r l b . of
fo od
............................

8*

8*

8*

8*

8*

8*

3.4

3.1

3.2

3.3

2.4

2.1

C o s t p e r l b . of
f i s h g a i n . (.cents). .

27*

25*

26*

26*

19*

17*

P e r c e n t of f i s h
g a i n ............................

28.9

31.2

20.5

19.4

23.0

25.2

A m o u n t of fo od f e d :
P e l l e t s ..............
M e a t .....................
T otal
..................

31.1
7. 6
38.7

30.0
7.5
37,5

28.0
5.6
33.6

27.0
5.6
32.6

28.0
5.6
33.6

27.0
5.6
32.6

.

4.9

4.8

2.9

2.9

2.6

2.5

F .)

52

52

49

49

45

45

N u m b er at s ta r t .
N u m b e r at end

C onversion

. . . .

P e r c e n t of b o d y
w eight fed daily
A verage w ater
t e m p e r a t u r e (°

D upli­
cation
11

D upli­
cation
12

D upli­
cation
11

42

T a b l e 6 (Co ntinued)

F o u r - Week: P e r io d
4
D upli­
cation
11

5
D upli­
cation
12

D upli­
cation
11

6
D upli­
cation
12

D upli­
cation
11

7
D upli­
cation
12

D upli­
cation
11

D upli­
cation
12

994

992

994

991

992

98 8

98 8

987

994

991

99 2

98 8

98 8

987

98 6

98 3

91.7

96.7

107.0

108.0

130.5

130.5

144.9

144.4

75.7

77.0

91.7

96.7

107.0

108.0

130.5

130.5

16.0

19.7

15.3

11 . 3

23.5

22.5

14.4

13 . 9

8*

8$

8$

8$

8$

8$

8$

8$

2.2

1. 7

2.2

2.9

1.7

1.7

2.5

2.5

18$

14$

18$

23$

13$

14$

2 0$

2 0$

21.1

25.6

16.7

11.7

21.7

20.8

11.0

10.7

28.0
7.0
35.0

27.0
7.0
34.0

28.0
5.6
33.6

27.0
5.6
32.6

33.2
5.6
38.8

33.0
5.6
38.6

30.2
5.6
35.8

29.2
5.6
34.8

2.0

1. 8

1.6

1.5

1.6

1.5

1.3

1.3

43

43

41

41

42

42

48

48

43
T a b l e 7.

P e r f o r m a n c e of v a r i o u s d i e t s d u r i n g a p e r i o d
eig h t w e e k s w h en fed to r a in b o w t r o u t .

of tw e n ty -

D iet
item
1

1

2

2

N u m b e r a t a t a r t ................................

1000

100Q

1000

1000

N u m b e r a t e n d ...................................

863

864

911

88Q

W eight at end

................................

144.9

144.4

164.0

163.5

W eight at a t a r t

................................

39.6

39.3

39.9

36.6

G ain in w eight

................................

105.3

105.3

1£ 4 . 1

126.9

C o a t p e r p o u n d o f f o o d ..............

7*

7*

00

8*

..........................................

2.4

2.4

1.4

1.4

C o a t p e r pound of f i s h g a in
(cents)
..........................................

16*

16*

11*

11*

................................

266.0

267.4

311.0

346.7

F o o d p r o p o r t i o n s fed:
M e a t (pet.)
...................................
P e l l e t s ( p e t . ) ................................

17.1
82.9

16.8
83.2

25.7
74.3

23.7
76.3

Conve r a io n

P e r c e n t of g a i n

A verage w ater te m p e ra tu re
P e r c e n t of r e c o rd e d

. .

lo ss . . . .

47

47

1.4

i.7

4.3

2.5

P e r c e n t of u n a c c o u n t a b l e l o s s .

12 . 3

11 .9

4.6

9. 5

P e r c e n t of t o t a l m o r t a l i t y

13 .7

13.. 6

8.9

12.0

. „ ,

44

T a b l e 7 (Con tinued )

D iet
3

3

4

4

5

6

7

8

100 0

1000

10 0 0

963

92 2

81 6

934

a

823

a

948

169.0

133.5

115.0

139.0

130.5

134.0

156.0

15 8 . 5

38.1

36.5

29.1

35.5

34.5

31.3

38.5

39.5

130.9

97.0

85.9

103.5

96.0

102.7

117.5

119.0
14*

00
-TV

1000

7*

-o*
00

10 0 0

CO

100Q

-u00

1000

-u~
00

1000

8*:

1. 3

1. 6

1.6

1.5

1 .6

1.5

2.0

3.0

11*

12*

13*

13*

11*

12*

16*

42*

343.5

265.8

295.2

291.5

278.3

328.1

305.1

301.2

24.4
75.6

26.9
73.1

28.8
71.2

26.3

16 .2
83.8

25.9
74.1

17.1
82.9

100
a

47

47

47

47

73.7

47

47
2.6

1. 9

3.Q

4.5

a

4.0

a

3.2

1.1

5.9

15 .1

2.1

a

13.7

a

2.0

3-. 7

7.8

18.4

6.6

a

17.7

a

5.2

45
c o n c u r r e n t l y ' to t w o d i f f e r e n t g r o u p s

of r a i n b o w t r o u t a r e p r e s e n t e d

i n d e t a i l to o f f e r a s a m p l e of t h e m e t h o d s
grow th-producing

v a l u e of a p a r t i c u l a r d i e t .

w e r e f e d to d u p l i c a t e g r o u p s , a n d t h e
c o rd e d in Table

used for determ ining

7 in duplicate.

D iets

the

1, 2 , 3, a n d 4

su m m ary for

each was

re­

C o n v e rs io n f a c t o r s in T able 6 a r e

c a l c u l a t e d b y d i v i d i n g t h e p o u n d s of f o o d f e d d u r i n g t h e m o n t h by
t h e g a i n i n w e i g h t of f i s h .

The c o n v e rsio n fa c to rs

in T able

7 are

c a l c u l a t e d b y d i v i d i n g t h e t o t a l p o u n d s of f o o d f e d f o r t h e t w e n t y - e i g h t
w e e k p e r i o d b y t h e t o t a l g a i n i n w e i g h t of f i s h .
P e r c e n t a g e g a i n is c a l c u l a t e d by dividing the g a in in w e ig h t by
t h e w e i g h t of f i s h a t s t a r t o f e a c h p e r i o d a n d m u l t i p l y i n g t h e r e s u l t
b y 10 0 .
F o o d f e d d a i l y i n p e r c e n t of b o d y w e i g h t i s c a l c u l a t e d b y d i ­
v id in g th e t o t a l p o u n d s f e d d u r i n g th e p e r i o d b y th e n u m b e r of d a y s
i n th e . p e r i o d ;

th is is d iv id ed by the a v e r a g e

w e i g h t of f i s h o n h a n d

w h i c h i s o b t a i n e d b y a v e r a g i n g th e w e i g h t of f i s h o n h a n d a t th e
b eginning a n d end of the p e rio d .
6 and

7 are

self-explanatory.

A graphic
average

O ther conditions noted in T ab les

c o m p a r i s o n of p e r c e n t g a i n i n w e i g h t i n r e l a t i o n to

w a t e r t e m p e r a t u r e a n d a m o u n t o f f o o d f e d i n p e r c e n t of b o d y

w eight p e r

day is given in F ig u re

2.

The curves

r e p r e s e n t the r e ­

s u l t s o f f e e d i n g D i e t 1 c o n c u r r e n t l y to t w o d i f f e r e n t g r o u p s

of r a i n b o w

46

WjB s 'W £ £ rj&k

trout.

T h e a m o u n t of f o o d f e d i n p e r c e n t of b o d y w e i g h t p e r d a y

in clu d ed both p e lle ts an d m e a t.
a t the beginning

of t h e

the

(T ables

s h o w n , t h e a m o u n t of f o o d f e d

e x p e r im e n t a p p a re n tly w as in e x c e s s and a

c e r ta in p o rtio n w as w asted.
factor

As

6 a n d 7).

This is

r e f le c te d in a high c o n v e r s io n

T h e r e f o r e , t h e a m o u n t of t h e f o o d f e d a t

e n d of t h e f i r s t m o n t h w a s r e d u c e d a p p r o x i m a t e l y o n e - t h i r d ,

resulting

in l e s s

w asting

of f o o d .

Inasm uch as

t h e r a t e of g a i n r e ­

m a i n e d u n c h a n g e d , the a s s u m p t i o n th a t fo o d w as being fed in e x c e s s
w as c o rre c t.

T h i s a m o u n t w a s f e d d u r i n g t h e r e m a i n d e r of t h e e x ­

p e r i m e n t a l p e r i o d i n a n a t t e m p t to p r o d u c e a m a r k e d c h a n g e i n r a t e
of g a i n o f w e i g h t a n d e s t a b l i s h a d e f i n i t e r e q u i r e m e n t i n d a i l y v o l ­
u m e of f o o d i n t a k e f o r a p a r t i c u l a r s i z e f i s h a t a d e f i n i t e w a t e r t e m ­
perature.

T h i s a p p e a r e d to o c c u r

of f e e d i n g

w h e n t h e a m o u n t of f o o d w a s

body w eight p e r day.

The w a te r

near

t h e e n d of t h e s i x t h m o n t h
e q u a l to 1.5 p e r c e n t of f i s h

tem p eratu re

at that tim e w as

42°

and risin g .
It is
p er day fro m

evident (Table

6) t h a t r e d u c i n g t h e a m o u n t of f o o d f e d

4 . 8 to 2 . 9 p e r c e n t a t a w a t e r t e m p e r a t u r e

h a d no e f f e c t on the r a t e

o f g a i n i n w e i g h t of r a i n b o w

ing

sev en te en fish p e r pound.

the

w ater te m p e ra tu re

m onth

sh o w n , the

rate

From

rose from

42°

F igure

of 49°

F.

trout a v e ra g ­

2 (also o th e rs ) , w hen

F . t o 48° F .

during

o f g a i n i n w e i g h t f e l l off s l i g h t l y .

the l a s t
At this

F.

48
tim e

t h e a m o u n t of f o o d f e d i n p e r c e n t of b o d y w e i g h t w a s

r e d u c t io n in the r a t e
w as not adequate
ture

The

of g a i n i n d i c a t e s t h a t t h e a m o u n t o f f o o d f e d

to m a i n t a i n a s t e a d y g r o w t h r a t e

w ith t r o u t a v e ra g in g

necessary

1. 3.

daily a t th e se

sev e n p e r pound.

T h e a m o u n t of f o o d

w ater te m p e ra tu re s

(as d e te r m in e d by n u m b e r s

at this t e m p e r a ­

and for

p e r pound) a p p e a r s

this

size fish

to b e b e t w e e n 2 . 9

a n d 1 .5 p e r c e n t of b o d y w e i g h t .
The p erfo rm an ce

of D i e t s

2 t h r o u g h 7, i n c l u s i v e , w i t h r e s p e c t

to p e r c e n t g a i n i n w e i g h t , w a t e r t e m p e r a t u r e

a n d a m o u n t of f o o d

f e d i n p e r c e n t of b o d y w e i g h t p e r d a y w h e n c o m p a r e d to D i e t 8
(control) is g ra p h ic a lly p r e s e n te d in F ig u r e s

3 to 9, i n c l u s i v e .

It

w ill b e n o te d th a t D ie t 2 a n d D ie t 6 p r o d u c e d g r e a t e r g a in s p e r
o f t i m e t h a n a n y of t h e o t h e r d i e t s w i t h D i e t s
order.

The a v era g e

was le ss

rate

3 and 4 nex t in that

of g r o w t h p r o d u c e d b y D i e t s

1, 5, a n d 7

t h a n t h a t of D i e t 8,

F ig u re

10 c o m p a r e s

th e r a t e of g r o w t h in p e r c e n t of b o d y

w e i g h t g a i n e d p e r t w e n t y - e i g h t d a y p e r i o d of D i e t s
11 , of D i e t s

3 a n d 4; a n d F i g u r e

rem em bered

(Table

D iets

unit

1 2 , of D i e t s

1 a n d 2; F i g u r e

6 a n d 7.

It should be

4) t h a t t h e o n l y d i f f e r e n c e i n t h e f o r m u l a t i o n of

1 a n d 2 w a s th e u s e of tw o d i f f e r e n t y e a s t p r o d u c t s .

c o n ta in e d to r u la y e a s t and D iet 2 co n tain ed b r e w e r s

yeast.

D iet 1

49

MO

UiLEGB.CB.ddJT,

40

.to /te s e . T £ M B E E 9 n 'J$A\

j&jg 0 .& j'

~Ei ~sVi*. 4 ^

^

50

hS

M
T& ci& aL

51

A . ( 7 L t 7£ f t £ ilM J L

^ tQ

60

Vm ? £ A 7£ W t WA W V& ?

$ & O J L Y -£ '£ & C £ i V&

m

Ttf>Orwt-'&jp C / £ / r £ # £ W r # •

52

53

54

i
m

•m s d m i

k m c M zsiZ
/zz/p

BX -&

& m '&
££#*

55

e : / l & W j t r< 2 W . T & C Q Z

/v r

56

57

/* > £ je C j£ /V 7 -

58

59
As

shown in F ig u re

h ig h e r th a n D iet 1 d u ring
th is out (Table

8).

10 , D i e t 2 p r o d u c e d g a i n s c o n s i d e r a b l y
this p e rio d .

F ig u re

11

S tatistical an aly sis b e a rs

sh o w s no d i f f e r e n c e , a s d e t e r m i n e d

by p e r c e n t g a i n i n w e ig h t, b e t w e e n the two y e a s t s
m e al was

substituted fo r

cottonseed m eal.

tin, p r o d u c e d f is h a t a s t e a d i e r

rate

containing a s ta b iliz e d fa t (F ig u re

D iet

w h e n s o y b e a n o il
6, c o n t a i n i n g g e l a ­

of g a i n i n w e i g h t t h a n D i e t 7,

12).

D iet 5 show ed a ra te

g a i n o f w e i g h t c o n s i s t e n t l y l o w e r t h a n D i e t 8.

It is in t e r e s t i n g

note th a t the g ro w th c u r v e s f o r all d ie ts d e c lin e d f r o m
the

in
to

t h e f i f t h to

sixth m o n th .
The re s u lts

of s t a t i s t i c a l a n a l y s i s f o r d i f f e r e n c e s

in p e r c e n t

g ain in w eight (b ased on c u m u la tiv e p e r c e n t gain p e r tw o -w e e k period)
b e tw e e n g ro u p s fe d p e lle te d diets and a ra w beef liv e r diet and b e ­
tw een gro u p s fed v a rio u s p ellete d diets
difference
ference

(t = 2 . 9 6 * * ) b e t w e e n D i e t s

show ed a highly

significant

1 and 2 and a significant dif­

( c a l c u l a t e d t = 2 .0 1 , t a b u l a r t = 2.056) b e t w e e n D ie ts

8 (control,

Table

significance.
nificantly.

8).

A ll o th e r

The d if f e r e n c e b e tw e e n D iets
diets

c o m p a r e d in T able

S tatistical an aly ses

t r a y e d in F i g u r e s

2 and

6 and 8 approached

8 did n o t d iffe r

s u p p o r t the g r a p h i c

sig­

differences p o r ­

3 t o 12 , i n c l u s i v e .

I n M i c h i g a n , i t i s t h e p o l i c y t o r e a r a l a r g e p o r t i o n of t h e
total

s u p p l y of t r o u t to a l e g a l

s i z e of s e v e n i n c h e s b e f o r e p l a n t i n g

60
Table

8.

T he r e s u l t s of a s t a t i s t i c a l a n a l y s i s fo r d if f e r e n c e s in the
p e r c e n t a g e g a i n s i n w e i g h t b e t w e e n g r o u p s fe d p e l l e t e d
d i e t s and a r a w b e e f l i v e r d i e t and b e t w e e n g r o u p s fed
pelleted d ie ts.

Diet
C om parisons

T otal
C um ulative
P c t . G ain

.a
1 nb
1 and 8

139.4--143.3

D iet

1, -

4.3

1.27

a

P et. L o ss
o r G ain

C alculated
"t"
V alues

and

8

1 5 2 . 9 '* - 1 4 3 . 3

D ie t 2, +

9.3

2.01

3

and

8

1 5 1 .6 — 143.3

D i e t 3, +

8. 3

1.65

4

and

8

143.5 — 143.3

D iet 4, +

0.2

1.30

8

153.8 — 143.3

D i e t 6 , + 10 .5

1. 96

1 and 2

139.4— 152.9

D iet

1, -

13.5

2.96**

3 and 4

151.6 — 143.5

D ie t 3, +

7.9

2

6 and

£L
R eplicated diets.
C ontrol diet.
T abular t
T abular t

05

, 2.6 d . f . = 2 . 0 5 6 ^
, 26 d .f. = 2 .7 7 9 * *

(significant).
(highly s ig n if i c a n t ) .

1.22

61
them

in s t r e a m s

experim ents
th is

size.

and lakes,

w ere
Table

of l e g a l -

t e r m i n a t e d w h e n t h e m a j o r i t y of f i s h h a d r e a c h e d
9 p r e s e n t s by g ro u p the n u m b e r and total w eight

and s u b le g a l-s iz e d rainbow trout,

e n d of th e

experim ent,

reco rd ed lo sses

ceding
8 are

r e c o r d e d lo s s , and unaccountable lo ss.

shown in T ables

experim ents.

of d e a t h a s

9,

10, 1 1, a n d 12 w e r e d e r i v e d f r o m

R esults fro m

show n in T a b les

g ro u p s fed D iets

9 a.nd 10, a n d f r o m

11 a n d 12.
m alnutrition.

w ere

operated as
lo sses.

I t w a s n e v e r p o s s i b l e to d i a g n o s e t h e
The

e x t r e m e l y high and v a r ie d u n ­
defies an a ly sis.

All

except m a n him self;

therefore,

it a p p e a r s

that

d i f f e r e n c e s i n l e n g t h of f i s h i n e a c h g r o u p c a n n i b a l i s m
the m a j o r f a c t o r in p r o d u c i n g the high u n a c c o u n ta b le

Since

an accu rate

1, 2 , 3,

co n d u cted in sid e a h a tc h e ry building p rev e n tin g

lo s s e s by p re d a to rs
d u e to l a r g e

the p r e ­

1, 2, 3, 4, 6, a n d

g ro u p s fed D iets

accountable lo s s e s betw een groups p ra c tic a lly
experim ents

The

h an d lin g d u rin g tank cle an in g a n d w eighing o p e r a tio n s .

6, a n d 8 in T a b l e s
cause

the c o u n t e d to t a l a t the

c o n s i s t e d of f i s h w h i c h d i e d f r o m j u m p i n g o u t of

the ta n k a n d f r o m
The data

S i n c e t h i s i s t h e p o l i c y , m a n y of t h e

special p rec a u tio n ary m e a s u re s

w e r e t a k e n to g a i n

h a n d c o u n t b e f o r e , d u r i n g , a n d a t t h e e n d of t h e e x p e r i -

i^ignt b y o n e p e r s o n v e r i f y i n g t h e c o u n t t a k e n b y a n o t h e r a t t h e s a m e
tim e and at s e p a ra te
in Table

9 are

tim es,

accurate.

i t i s f e l t t h e n u m b e r s of f i s h p r e s e n t e d

62
Table

9.

C o m p a r i s o n of n u m b e r and w e ig h t of l e g a l - and s u b l e g a l ­
s iz e d t r o u t in g r o u p s r e c e i v i n g five d i f f e r e n t p e lle te d d i e t s
and one m e a t d ie t.

L e g a l Size
D iet

S ublegal Size^

no.)

Re­
corded
Loss
(n o.)

Unac­
count­
able
Loss
(no.)

Hand
Count
(total

Wt.
(lbs.)

No.

Wt.
(lbs.)

No.

1

13 0

552

31

311

863

14

123

1

147

71 3

11

151

86 4

17

119

2

149

728

13

183

911

43

46

2

150

72 2

12

158

88 0

25

95

3

152

723

16

240

963

26

11

3

11 8

533

18

389

92 2

19

59

4

99

512

17

303

81 6

30

151

4

125

631

18

303

934

45

21

6

167

70 5

9

118

823

40

137

8

16 6

805

12

143

948

32

20

a M ore than

7 in ch es long.

jL
L e s s th a n 7 i n c h e s long.

63
T able

10 .

C o m p a r i s o n of p e r c e n t a g e of l e g a l a n d s u b l e g a i r a i n b o w
t r o u t fed five d i f f e r e n t p e lle te d d i e t s and one m e a t d ie t.

L e g a l S izea

S u b le g a i Size

Unaccount­
able
Loss
(pet.)

w t.

By
No.

By
Wt.

By
No.

Re­
corded
Loss
(pet.)

1

80.7

64.0

19.3

36.0

1.4

12 . 3

1

93.0

82.4

7.0

17.6

1.7

11.9

2

92.0

79.9

8.0

21.1

4.3

4.6

2

92.6

82.0

7.4

18.0

2.5

9 .5

3

90.5

75.0

9. 5

25.0

2.6

1.1

3

86.8

57.8

13.2

42.2

1.9

5.9

4

85.3

62.7

14. 7

37,3

3.0

15.1

4

87.4

67.6

12.6

32.4

4.5

2.1

6

94.9

85.6

5.1

14.4

4.0

13 .7

8

93.2

84.9

6.8

15.1

3.2

2.0

D iet

By

a M o r e th a n 7 i n c h e s long.
^ L e s s th a n 7 i n c h e s long.

64
G rading
the

e a c h l o t o f f i s h to a u n i f o r m

s i z e a t t h e b e g i n n i n g of

e x p e r i m e n t w o u ld , no d o u b t, d i r e c t l y p r e v e n t c a n n i b a l i s m b y e s ­

ta b lish in g m ore

equal com petition.

in s e v e r a l g ro u p s
caused a g reater
groups w ere

H o w e v e r , the f a c t r e m a i n s th a t

som e f a c to r o th e r than size d iffe re n c e s
cannibalistic

could have

u rg e than in o th e r g ro u p s .

tr e a t e d in a n id e n tic a l m a n n e r,

f a c t o r m a y h a v e o p e r a t e d to. s t i m u l a t e o r

Since all

it a p p e a r s th a t a d i e t a r y

depress

this in s tin c t,

o n e g r o u p of t r o u t f e d D i e t 3 ( T a b l e 9) o n l y e l e v e n t r o u t w e r e
accounted fo r.

the

c o u l d b e d u e to a h i g h e r p e r c e n t a g e

s u b s t i t u t i o n of s o y b e a n o i l m e a l f o r c o t t o n s e e d

m e a l , a n d t h e c o m p l e t e l a c k of c o n d e n s e d f i s h
careful
the

un­

A f i r s t g l a n c e a t t h e c o m p o s i t i o n of D i e t 3 s u g g e s t s

that low u n acc o u n tab le l o s s e s
of f i s h m e a l ,

In

solubles.

s c r u t i n y of t h e c o m p o s i t i o n of o t h e r d i e t s

r e s u l t s of d u p l i c a t i o n ( T a b l e

9 ), i t w a s

(Table

A fter m o re
4) a n d of

seen that g ro u p s

receiving

d i e t s o t h e r t h a n D i e t 3, w h i c h c o n t a i n e d t h e s a m e p e r c e n t a g e of
these in g red ien ts, also

sh o w ed high u n acc o u n tab le l o s s e s .

p re s e n te d h e re offer inconclusive
ent operated m o re

The data

e v id en ce th a t one d i e t a r y c o n s titu ­

t h a n a n o t h e r to i n s t i g a t e c a n n i b a l i s m ;

nevertheless,

i t a p p e a r s p r o b a b l e t h a t o n e o r p e r h a p s a c o m b i n a t i o n of d i e t a r y
factors

in s e v e r a l d ie ts a ffe c te d the n a tu ra l c a n n ib a listic

By fu rth er
this

e x p e r i m e n t a t i o n i t i s h o p e d to f i n d a d i e t a r y

m a jo r problem .

instinct.
solution fo r

65
The m o s t sig n ific a n t p o in ts
siderable

v a r i a t i o n of l e g a l -

fed v ario u s

diets.

and

show n in T able

9 r e s t in the c o n ­

su b le g a l-siz e d tro u t betw een groups

D iet 6 p ro d u c e d a h ig h e r p e rc e n ta g e

s i z e d f i s h t h a n a n y of t h e o t h e r s

(Table

10).

of l e g a l ­

Since p e r c e n t is b a s e d

on a to tal v a lu e , it should b e p o in ted out th a t D iet 8 (raw b eef liv e r)
produced a la rg e r
than

D iet

6.

n u m b e r of l e g a l - s i z e d f i s h b u t a l o w e r p e r c e n t

D iets

6, 8, 1, a n d 2, i n t h a t o r d e r , p r o d u c e d t h e

h i g h e s t p e r c e n t a g e of l e g a l - s i z e d fish ;
R ecorded lo sses

in g ro u p s re c e iv in g

D iets

D iet 1 w e r e the lo w e st, and

th o s e r e c e iv in g D ie t 4 w e r e the h ig h e s t.
D iet 3 sh o w e d the lo w e s t to ta l lo s s
T able

11 s h o w s t h e r a n g e

in in c h e s a t the
here

m erely

H ow ever, one group fed

of a n y g r o u p .

in in c h e s a n d the a v e r a g e le n g th

s t a r t a n d e n d of t h e

to p o in t out the

3 a n d 4, t h e l o w e s t .

experim ent.

extrem e

It is p r e s e n t e d

r a n g e i n l e n g t h a t t h e e n d of

th e p e r i o d w h e n c o m p a r e d to th e l e n g t h a t th e s t a r t a n d th a t a p a r t
of the

sm all th re e -in c h group w ere

tw en ty -eig h t w eek p erio d .
m onths
th ree-

old.

s t i l l p r e s e n t a t t h e e n d of t h e

At th at tim e

these

trout w ere

sixteen

H o w e v e r , i n u n s o r t e d f i s h , t h e p r e s e n c e of a f e w

t o f o u r - i n c h f i s h i n a g r o u p of r a i n b o w t r o u t s i x t e e n m o n t h s

old is not u n c o m m o n .
T h e n u m b e r a n d a v e r a g e l e n g t h of s o r t e d f i s h b y s i z e g r o u p s
a t the

e n d of a s i x - m o n t h

e x p e rim e n ta l p e rio d is

show n in T ab le

12.

66
T able

11 .

A v e r a g e w e ig h t and le n g th of r a in b o w t r o u t fed v a r i o u s
d i e t s a t t h e s t a r t an d end of a s i x - m o n t h p e r i o d .

End

Start
D iet

Range
(In.)

Avg.
L ength

Avg.
Wt.

(In.)

(8.)

Range
(In.)

Avg.
Length

Avg.
Wt.

(in. )

(g.)

6.4

59.4

6.3

54.5

3.2--10.2

6.0

55,0

14.8

3 .4--9.7

6.0

54.4

19 .9

3.2 — 8. 5

5.8

54.5

2

3 .0 — 4.7

4.06

17.8

3

2 . 9 — 5.1

4.50

17.3

6

3 .0 — 5.0

4.40

8

3.1--5.1

4.53

o"
(
1
1

17.9

1—

4.80

00

3.1 — 5 . 9

CO

3.8--9.2

1

67
N u m b e r a n d a v e r a g e l e n g t h of s o r t e d r a i n b o w t r o u t a t
th e end of a s i x - m o n t h e x p e r i m e n t a l p e r i o d .

L e n g th (inches)
Range

T otal
No.

Wt.
(lbs.

54
64
1 94
237
70

2.6
3.0
7.4
8.8
3.3

269
187
231
231
294

23.0
15 . 3
18 .5
20.0
24.7

65 7
672
504
494
614

99.3
123.9
85.9
86.7
95.6

Avg..

Sm all

I
2
3

6
8

3 . 8 - - 5 .9
3 . 8 - - 5 .9
3 . 2 - - 5.7
3 .4 — 5.7
3.2--6.1

5.3
4.9
4. 5
4.6
4.7
M edium

1
2
3

6
8

5 .3 --7 .3
4.9--7.2
5.Q --7.5
5 .2--7 .3
5 .1 - - 7 . 3

6.0
5.9
5. 7
6.0
6.0
L arge

1
2
3

6
8

6 .0--9.2
6 .1 --1 0 .4
6.2 --1 0 .2
6.3- -9.7
5 . 6 — 8. 5

7.9
7.8
7.7
7.5
6. 8
T otal N um ber

1

2
3

980
94 3
929
962
97 8

W hen com paring

D i e t 8 w ith p e l l e t e d d r y d i e t s , the a v e r a g e le n g th

of l a r g e f i s h p r o d u c e d b y t h e
one inch le s s

than those f r o m

f is h in the m e d iu m
as w ere

those

raw beef liver

size

in the

groups

sm all

groups
w ere

diet w as ap p ro x im ate ly

receiving dry p ellets.
sim ilar

size g ro u p s.

All

i n l e n g t h to e a c h o t h e r

It s h o u l d b e n o t e d , n e v e r ­

t h e l e s s , t h a t e v e n t h o u g h the l e g a l - s i z e d f i s h i n the l i v e r - f e d g r o u p
w ere
the

s h o r te r one m o n th b efo re

s a m e p e r c e n t of l e g a l - s i z e d t r o u t w e r e p r e s e n t a t t h e e n d of

tw enty-eight w eeks as th e re
10).

t e r m i n a t i o n of t h e e x p e r i m e n t a l m o s t

This

w e r e i n the g r o u p s f e d p e l l e t s

show s that m o r e fis h f r o m

the m e d i u m

l i v e r g a i n e d i n l e n g t h t o b e c o m e p a r t of t h e l a r g e
the l a s t m o n t h th a n th o s e f e d the o t h e r d ie ts .

(Table

size group fed
size group during

69
Table

13.

C o n d i t i o n f a c t o r of r a i n b o w t r o u t fed five d i f f e r e n t d i e t s
o y e r a p e r i o d of t w e n t y - f o u r w e e k s .

D iet

S tart

End

1

0.99

1.34

0. 3 5

2

1.63

1.76

0.13

3

1.17

1. 5 2

0. 3 5

6

1. 0 5

1.52

0.47

8

1.30

1.99

0.69

ence

70
T able

14 .

C o n d i t i o n f a c t o r of t h r e e s i z e g r o u p s of r a i n b o w t r o u t
fed v a r i o u s d ie ts .

D iet

C enti­
m eters

G ram s

A

Sm all
1
2
3

13.5
12.4
11.6

21.8
21.2
17.3

6
8a

11.8
11.9

16.9
21.4

0.89
1.11
1.1 1
1.02
1.27

38.8
37.1
36.3
39.3
38.1

1.10
1.12
1.14
1.08
1.08

68.6
83.5
77.2
79.7
70.6

0.86
1.06
1.03
1.14
1.36

M edium
1
2
3
6
8a

15.2
14.9
14.7
15.4
15.2
Large

1
2
3
6
8a

C o n tro l.

20.0
19.9
19.6
19.1
17.3

e v a l u a t io n

It is a c u s t o m a r y p r a c t i c e

of

growth

to e v a l u a t e g r o w t h b y w e i g h t a l o n e

in M ichigan h a tc h e rie s .

On a production scale

th is is p r o b a b l y the

m o s t p r a c t ic a l m ethod.

H o w e v er, w eight alone

d o e s not g iv e the

n e c e s s a ry in fo rm a tio n when attem pting

to e v a l u a t e a d i e t .

Length

m e a s u r e m e n t s , c h e m i c a l a n a l y s i s o f v a r i o u s i n d i v i d u a l p a r t s of t h e
body, and m o rta lity a re
S in ce, in th is

necessary

to d e t e r m i n e t h e v a l u e of a d i e t .

s t u d y , g r o w t h i n r e l a t i o n to g a i n i n w e i g h t a n d l e n g t h

w a s u s e d a s a n i n d e x of d i e t v a l u e , i t i s n e c e s s a r y
scribe

s o m e a s p e c t s of t r o u t g r o w t h .
The ra te

of g r o w t h o f t h e r a t , c h i c k e n , a n d p i g i s m o r e

t h a n t h a t of t r o u t .

feeding

and ex trem e

reg u lar

ra te is a s s u m e d a s

curve
are

e t a l ., 1 9 2 8 ) .

w ater te m p e ra tu re s have a sim ilar

R estricted

effect.

T itco m b points out that since

slo w e r th an o th e r an im al g row th and th e re fo re

rep resen tin g

A

so o n as a n a d e q u a te d ie t is p ro v id e d ,

the p o w e r to g r o w is n o t lo s t.

tro u t grow th is

rapid

T r o u t c a n liv e f o r long p e r i o d s w ith o u t exhibiting

g ro w th w hen p la c e d on a faulty d iet (Titcom b

for

to b r i e f l y d e ­

a

tro u t g ro w th has a m o re g rad u al slope, tro u t

ex cellent ex p erim en tal an im als for

71

studies on gro w th a c c e le ra tio n .

72
O n e f a c t o r of o u t s t a n d i n g i m p o r t a n c e i n t r o u t p r o d u c t i o n i s
m axim um

grow th ra te .

grow th ra te

It is b e lie v e d th a t in this

w a s n o t a t t a i n e d i n a n y of t h e g r o u p s .

tentional r e s t r i c t e d feeding w as
mum
the

study m a x i m u m

grow th;

c a r r i e d out th a t did not p e r m i t m a x i ­

th e re fo re , a d e p re s s e d grow th ra te

experim ent.

ing p r a c t i c e s .

This a p p e a rs
To be

A t y p e of u n i n ­

to b e t h e c a s e

o c c u r r e d throughout

in m o s t h a t c h e r y f e e d ­

s u r e , a n a d e q u a t e a m o u n t of f o o d w a s f e d

d u rin g any one fe e d in g p e r io d , and in m a n y c a s e s

not all the food

w a s c o n s u m e d , b u t the f a c t r e m a i n e d th a t t r o u t w ould take food
again a v ery
tim es

s h o rt tim e la te r.

a day when v e ry

g radually being
feedings a r e

sm all,

reduced as

given p e r day.

at present necessary,
d em onstrated.

feeding

resem ble

m ore

fed ad libitum .
accu rate
an im als.

t r o u t b e c o m e o l d e r u n til one to t h r e e
B e c a u s e of t h e s e p r a c t i c e s ,

It is p lan n ed f o r fu tu re

i n a n a t t e m p t to d e t e r m i n e

closely

of t r o u t .

ev en though

of t r o u t c a n n o t b e

experim ents

w hich d is p e n s e s

o n the g r o w th r a t e

seven

t h e n u m b e r of f e e d i n g p e r i o d s p e r d a y

the m a x i m u m g r o w th r a t e

au to m atic feeding device
short in terv als

U sually tr o u t a r e fe d six o r

to e m p l o y a n

s m a l l a m o u n t s of f o o d a t
t h e e f f e c t of c o n t i n u o u s

T h i s t y p e of f e e d i n g w o u l d

the ty p e u s e d f o r o t h e r a n i m a l s

W i t h t h i s m e t h o d , i t i s h o p e d to a c q u i r e

w hich a r e
a m ore

c o m p a r i s o n of g r o w t h r a t e b e t w e e n t r o u t an d o t h e r d o m e s t ic

CO N D ITIO N F A C T O R O F RAINBOW

T h e c o n d itio n f a c t o r is a t e r m

TROUT

u s e d to e x p r e s s

the r e l a t i o n ­

sh ip b e t w e e n the w e ig h t a n d le n g th of t r o u t ( T u n is o n an d P h i l l i p s ,
3
1939).

The fo rm u la

facto r w here

lOOy = A x

i s u s e d to c a l c u l a t e t h e c o n d i t i o n

y is the w e ig h t in g r a m s , x the

cen tim eters, and A rep resen ts

s t a n d a r d le n g th in

the c o n d itio n f a c t o r .

W ell-nourished

f i s h sh o u ld h av e a h ig h e r c o n d itio n fa c to r th an th o se w hich have
been starved.
creases.
and injury

U s u a l l y a s f i s h g r o w o l d e r the c o n d itio n f a c t o r in ­

Such f a c t o r s a s

sex,

spaw ning p e r io d , d is e a s e , cro w d in g ,

ca n influence the condition f a c to r .

C e r t a i n d i e t s , no d o u b t, i n f l u e n c e th is f a c t o r by the d i f f e r e n c e
i n f o o d e f f i c i e n c y d u e to d i f f e r e n t d i e t a r y
binations

m a y dep o sit m o re fa t than o th e rs

com binations.

Some co m ­

and produce a fish

h e a v i e r but n o t a s long a s a f i s h fe d a n o th e r diet.

In T able

Is

w ere sh o rter

show n th a t D iet 8 (control) p r o d u c e d tro u t w hich

12,

it
in

le n g th th a n th o s e p r o d u c e d b y the o th e r d ie ts .
In a n a t t e m p t to a n a l y z e

this d if f e r e n c e the co n d itio n f a c to r

w as calcu lated fo r a

g r o u p of t r o u t f e d e a c h of f i v e d i e t s a t t h e

s t a r t a n d e n d of the

e x p e r i m e n t ( T a b l e 1 3 ), a n d f o r t h r e e s i z e g r o u p s

o n the

sam e

d i e t s a t t h e e n d of t h e f i r s t s i x m o n t h s

73

(Table

14).

The

values p re s e n te d in Table
fish fro m
from

e a c h lot.

in

the a v e r a g e

The v alu e s p r e s e n te d in T able

t h e a v e r a g e of f i f t y f i s h i n t h r e e

of t h e f i v e d i e t g r o u p s .
in the

13 w e r e o b t a i n e d f r o m

of 100

14 w e r e o b t a i n e d

size g ro u p s p r e s e n t in each

It will be n o te d th a t t h e r e is a n i n c r e a s e

c o n d i t i o n f a c t o r i n a l l t h e g r o u p s a n d b e t w e e n a l l of t h e g r o u p s

Table

13.

G ross

e x a m i n a t i o n d u r i n g a n d a t t h e e n d of t h e e x p e r i ­

m e n t a l p e r i o d r e v e a l e d a l a r g e d e p o s i t of m e s e n t e r y f a t i n t h e l i v e r fed group.

T his

m i g h t h a v e b e e n t h e r e s u l t of a h i g h f a t - t o - p r o t e i n

r a ti o p r e s e n t in the l i v e r diet.

The liv e r was fed " a s

purchased";

th a t i s , w ith o u t r e m o v i n g e x c e s s fat.
Size g ro u p s

of t h e

sam e age

in condition fa c to r

(Table

14).

showed c o n sid e ra b le

variation

H ow ever, h e r e again it was d e m o n ­

s t r a t e d th a t D ie t 8 p r o d u c e d f is h in e ac h g ro u p w ith a c o n d itio n
factor

e q u a l to a n d g r e a t e r t h a n t h o s e f e d o t h e r d i e t s .

It i s c l e a r l y

s h o w n th a t d ie ts of the c o m p o s i t i o n u s e d h e r e w ill in flu e n c e
c o n d i t i o n f a c t o r of t r o u t n o t o n l y i n t h e l a r g e
the m e d iu m and

sm all as

w ell.

the

size g ro u p s b ut in

bro o k

T his

tr o u t

fe e d in g

e x pe r im e n t

e x p e r im e n t w as c a r r i e d out on a p ro d u c tio n sca le a t

M a r q u e t t e , M i c h i g a n , a n d w a s d e s i g n e d to s e r v e
w a s d e s i r e d to k n o w th e p e r f o r m a n c e
brook trout as

w ell a s

a dual p u rp o se .

It

of a p e l l e t e d d i e t w h e n f e d to

w h e n f e d to r a i n b o w t r o u t .

A lso,

since a

m e a t s u p p l e m e n t w a s u s e d p e r i o d i c a l l y , i t w a s d e s i g n e d to d e t e r ­
m ine

w h a t l e n g t h of t i m e c o u l d i n t e r v e n e b e t w e e n r a w

m e at feedings.

F o u r lo ts of 4,000 y o u n g - o f - t h e - y e a r b ro o k t r o u t w e r e p la c e d in
gravel-bottom

races

sufficiently la rg e

to c o m p e n s a t e f o r n o r m a l

g ro w th d u rin g the

e x p e r i m e n t a l p e r i o d w i t h o u t d a n g e r of o v e r ­

crow ding.

1A r e c e i v e d D i e t 1 f o u r d a y s a n d r a w b e e f l i v e r

G roup

one day p e r w eek.

G roup

IB

r e c e i v e d D iet 1 nine d ay s and r a w

b e e f l i v e r o n e d a y e v e r y two w e e k s , a n d G r o u p

1C r e c e i v e d D i e t 1

f o u r te e n d ay s and r a w beef liv e r one day e v e ry th re e
yeast and

weeks.

c o n s i s t i n g of 8 p e r c e n t

torula

s e rv e d a s the control.

( T h is c o n t r o l w a s u s e d b e c a u s e it w a s the

u s u a l p r a c t i c e a t t h e h a t c h e r y to u s e
h a tc h e r y d iet.)
m o v e d a t the
sim ilar

92 . p e r c e n t b e e f

A diet

this m i x tu r e f o r

T h e t o t a l n u m b e r of f i s h f r o m
end of e a c h m o n t h a n d w eig h ed .

to t h o s e p r e v i o u s l y d e s c r i b e d .

75

liver

the r e g u l a r

each group w ere r e ­
The m ethods

w ere

The e x p e rim e n ts w e re

76
conducted o v er a tw en ty -eig h t week period.
ce iv e d food in a m o u n ts

e q u a l to 3 . 6 p e r c e n t of b o d y w e i g h t p e r d a y

a n d the o th e r groups r e c e i v e d a m o u n ts
w eight p e r

e q u a l to 1 . 7 p e r c e n t of b o d y

day.

Table
eight w eeks
the

M eat control group r e ­

15 p r e s e n t s

of e x p e r i m e n t a t i o n .

effect that feeding

necessary.

the c o m p le te

A ll t h r e e

d a t a of a v e r a g e s

of t w e n t y -

T h e s e d a t a f u r n i s h i n f o r m a t i o n to

r a w m e a t once e v e r y five days
p ellet-fed groups

is not alw a y s

showed low er m o rta lity and

a h i g h e r r a t e o f g a i n a t a l o w e r c o s t p e r p o u n d of f i s h g r o w n t h a n
the

control group.
Table

16 s h o w s

conversion, a v e ra g e

the d if f e r e n c e

i n e a c h g r o u p i n r e s p e c t to

p e r c e n t g ain at tw e n ty -e ig h t day in te rv a ls , c o st

p e r p o u n d of t r o u t r e a r e d , a n d c o s t p e r h u n d r e d p o u n d s of d i e t .
c o s t p e r p o u n d of t r o u t in th e m e a t - f e d g r o u p w as a l m o s t t r i p l e
t h a t of p e l l e t - f e d f i s h , a n d a l o w e r p e r c e n t g a i n w a s

evident.

The

77
Table

15.

P e r f o r m a n c e of D i e t 1 w h e n s u p p l e m e n t e d w i t h r a w b e e f
l i v e r o n e d a y e v e r y w e e k , o n e d a y e v e r y t w o w e e k s , an d
one day e v e ry th re e w e e k s, using brook tro u t a s te s t
a n i m a l s (a v e ra g e w a te r t e m p e r a t u r e , 40.8° F .).

M eat
C o n t r o l 3-

G roup

Group
1A

IB

1C

4,000

4,000

4,000

4,000

N u m b e r a t e n d ...............

3,937

3,958

3,963

3,953

W eight a t end

...............

372.5

416.5

392

392.5

. . . .

144.5

150.0

139

141,0

N um ber at start

. . . .

W eight at s t a r t

G a in in w eight (lbs.)

.

228

266.5

253

251.5

C o s t p e r lb . of food

.

0,10

0.085

0.082

0.082

.................................
.................................

5.0
3.11

2.7
1.6

2.5
1.8

2.4

C o s t p e r l b . of f i s h
gain
....................................

0.50

0.24

0.20

0.20

P e r c e n t of f i s h . g a i n
( t o t a l ) ....................................

104.3

113.2

112.6

116.3

T o t a l l b s . of food fed;
Wet
. .............................
D ry
.................................

1 .160..0
810.0

652.0
452

585
47 3

568
477

P e r c e n t of b o d y
w e i g h t f e d ..........................

3. 6

1.8

1.6

1.6

1. 52

1.05

0.93

1.04

C onversion:
Wet
D ry

P e rc e n t m ortality

a M eat

. . .

c o n t r o l d i e t - - t o r u l a y e a s t , 8 p e r c e n t , and

l i v e r , 92 p e r c e n t - - f i v e

1.9

raw beef

days per week.

G r o u p h - - D ie t I fed 4 d a y s and r a w b e e f l i v e r 1 day p e r w eek.
G r o u p IB — D iet I fed 9 d a y s and r a w b e e f l i v e r 1 day e v e r y 2 w e e k s .
G r o u p 1 C - - D i e t I f e d 14 d a y s a n d r a w b e e f l i v e r 1 d a y e v e r y 3 w e e k s .

78
T able

16,

S u m m a r y of b r o o k t r o u t g r o w t h e x p e r i m e n t s
w a te r te m p e r a t u r e , 40,8° F .).

F e e d in g Schedule

W eeks

Co s t p e r
100 l b s .
of D ie t

(average

Cost p e r
P o u n d of
T rout
R eared

C onver­
sion

P e t. G ain
p e r 28
Day s

2 3£

2.7

23.0

D iet I
4 days m eat
1 d ay /w eek . „ .

28

$7.00

D iet I
9 days m eat
1 day/2 w eeks.

28

7.00

20

2.5

22.5

D iet I
14 d a y s m e a t
1 day/3 w eeks.

28

7.00

19

2.3

23.3

Y e a s t and m e a t
c o n t r o l 3..................

28

9.90

50

5.0

20.8

a 8 percent
p e r week.

torula

y e a s t — 92 p e r c e n t r a w b e e f l i v e r 5 d a y s

R E D B L O O D C E L L C O U N T IN B R O O K A N D R A I N B O W
T R O U T F E D VARIOUS D IE T S

E arly investigators
that tro u t fed

synthetic

W a l e s ari d M o o r e

s u c h a s M c C a y a n d D ill e y (1927) fo u n d

d ie ts f o r long p e r io d s

died in g r e a t n u m b e rs .

(1938) f o u n d t h a t a v e r y lo w r e d b lo o d c e ll c o u n t

o c c u r r e d in t r o u t w h e n f e d a c o m m e r c i a l dog fo o d w ithout m e a t f o r
long p e r i o d s .
T unison and P hillips

(1939) v e r y a s t u t e l y

brook tro u t fin g erlin g s w ere fed a
anem ia

showed that a fte r

synthetic diet and developed an

(600,000 r e d b lo o d c e lls p e r

c u b i c m i l l i m e t e r of b l o o d ) o v e r

a p e r i o d of n i n e w e e k s , t h e i r b l o o d c o u n t c o u l d b e r e s t o r e d

to 1 , 5 0 0 , 0 0 0

r e d b l o o d c e l l s p e r m i l l i m e t e r by a d d in g f r e s h b e e f l i v e r to the e x te n t
o f 5 0 p e r c e n t of t h e d i e t .
fly m a g g o ts a s w ell a s

The

sam e

in v e s tig a to rs found th a t h o u s e ­

raw beef liv e r w ere

r ic h in s o m e f a c t o r that

c u re d n u tritio n a l a n e m ia developed in tro u t but that v a rio u s liv e r
tracts

did not.

ex­

S i n c e t h e n i t h a s b e e n f o u n d b y T u n i s o n e t a l . (1 9 4 3 )

th a t m a n y unknow n f a c t o r s influence n u tritio n a l a n e m ia in tr o u t and
th a t s e v e r a l v ita m in s play a n im p o r ta n t ro le in its p re v e n tio n .

79

80
B lood Studies

D u rin g the p a s t s e v e r a l

years,

erythrocyte

counts w ere

p e r i o d i c a l l y f r o m f i s h f e d the d r y p e l le te d d ie ts a n d f r o m
raw beef liv er
The

o r r e d c o r p u s c le co u n ts w e re m a d e on blood

t a k e n f r o m th e s e v e r e d c a u d a l p e d u n c l e of tr o u t .

capillary

so lu tio n in a pip e tte

to t h e

diluting flu id .

0.5 m a r k

w i t h b l o o d a n d to t h e 101 m a r k w i t h the

A fter

w as p l a c e d on the co u n tin g

s h a k e n in the p i p e t t e f o r a

s h a k i n g , a s m a l l d r o p of d i l u t e d b l o o d

c h a m b e r of a n A O B r i g h t - L i i n e

t o m e t e r a n d t h e n u m b e r of r e d b l o o d c e l l s
This

cytes p e r

The blood was dilu ted

w ith a r e d b e a d by fillin g the

The d ilu ted blood w as

p e r i o d of tw o m i n u t e s .

scope.

those fed

d i e t s to e s t a b l i s h t h e r e d c e l l c o u n t s f o r t h e s e d i e t s .

erythrocyte

w ith H a y m e 's

taken

Haemocy-

counted u nder a m i c r o ­

v a l u e m u l t i p l i e d b y 1 0 , 0 0 0 g a v e t h e n u m b e r of e r y t h r o ­

c u b i c m i l l i m e t e r of f i s h b l o o d .

a n d 18 r e p r e s e n t s

E a c h value in T a b le s

a n a v e r a g e of t w o c o u n t s f r o m

each d

17

five fis h

fe d each diet.
R ainbow and brook
900,000 a r e
s h o w n in the

t r o u t w ith r e d blo o d c e ll counts below’

c o n sid e re d as approaching an anem ic
two t a b l e s b o t h s p e c i e s

condition.

As

of t r o u t f e d d r y p e l l e t e d d i e t s

fo r prolonged p eriods

contained n u m b e rs

of e r y t h r o c y t e s

the l i v e r - f e d g ro u p s .

N e i t h e r of t h e g r o u p s

e p u a l to

was co n sid ered as

81
T able

17.

N u m b e r of r e d blood
in b ro o k tro u t.

D ate

M a r c h 25,

c e l l s p e r c u b i c m i l l i m i t e r of b l o o d

G roup

la

..................

1953

G r o u p 2^

18 , 1 9 5 3

..........................

1,269,000

942,000

July

12,

.........................

1,130,000

844,000

...............

1,111,000

746,000

............... ..............

1,386,000

O ctober

14,

1953

February

4 , 1955

February

1 5 , 19 5 5

A p r i l 2 6 , 1955

A verage

3.

. „ . .

..................

....................................

3C

763,000

M ay

1953

G roup

1,074,000

1,201,000

1,170,000

1,116,000

1,190,000

D i e t 1, 4 d a y s a n d r a w b e e f l i v e r

824,000

1 day p e r w eek.

bP o r k li v e r and m e l t s , 5 0 -5 0 , 5 d a y s p e r w eek.
Raw beef liv e r 5 day s p e r week.

1,158,000

82
T able

18.

N u m b e r of r e d blood
in rainbow tro u t.

c e l l s p e r c u b i c m i l l i m e t e r of b l o o d

D ate

la

G r o u p 2^

1,123,000

1,120,000

. .

1,130,000

1,200,000

..........................

. ,

1,020,000

1,260,000

....................................

. . .

1,370,000

1,170,000

.........................

. . .

1,074,000

1,201,000

. ................................

. . .

1,170,000

1,116,000

1,148,000

1,177,800

M a y 2 0 , 1953

........................................

July 24,

........................................

1953

N o v e m b e r 6, 1953
A p r i l 30, 1954
F ebruary

1 5 , 195 5

A p r i l 2 6 , 1 95 5

Ave ra g e

a

..................................................

,
D iet 1,4 d a y s and ra w b e e f l i v e r

bRaw beef liv e r 5 days p e r w eek.

G roup

1 day p e r w eek.

83
suffering f r o m

nutritional an em ia

e x c e p t the b r o o k tr o u t fe d p o r k

liv er

and m e lt m ix tu res.

T h e t o t a l a v e r a g e of r e d b l o o d c e l l c o u n t s

from

this g ro u p w as a p p ro x im a te ly

366,000 c o u n ts b e lo w the a v e r a g e

of t h e o t h e r g r o u p s .
It s h o u ld b e n o te d th a t a l l g r o u p s f e d p e l l e t s in the p r e c e d i n g
experim ents
order

w e re fe d a r a w b eef liv e r diet one day e v e ry week.

to d e t e r m i n e

to w h a t e x t e n t t h i s

f e c t e d the e r y th r o c y te

In

raw m e a t supplem entation a f­

c o n t e n t of f i s h b l o o d a g r o u p of r a i n b o w a n d

b ro o k tro u t w hich had b e e n fed D iet 1 four days and ra w beef liv e r
o n e d a y p e r w e e k w e r e p l a c e d o n a n a l l - p e l l e t d i e t , D i e t 1, a n d w e r e
fe d f o r a p r o lo n g e d p e r io d w ithout
p resen ts

r a w m e a t of a n y t y p e .

T a b l e 19

t h e r e d c e l l c o u n t s a t t h e b e g i n n i n g a n d e n d of a t w e l v e ­

m o n t h p e r i o d of r a i n b o w a n d b r o o k t r o u t w h e n f e d a n a l l - p e l l e t d i e t .
For

com parison,

erythrocyte

counts taken f r o m

rainbow and brook

tro u t fed a ra w beef liv e r diet also a re p re se n te d .
one both

s p e c i e s of t r o u t f e d D i e t 1 s h o w e d h i g h e r r e d b l o o d c e l l

counts than those fed ra w beef liv er.
determ ined, g ro ss
ber

In all c a se s but

A lthough not s p e c ific a lly

ex am in atio n re v e a le d that th e re was a la rg e n u m ­

of c e l l f r a g m e n t s p r e s e n t i n t h e b l o o d f r o m t h e g r o u p s f e d p e l l e t s .
r

T h i s m a y b e d u e to a n u m b e r of r e a s o n s , a n d no e x p l a n a t i o n w i l l b e
a tte m p te d a t this

tim e.

84
Table

19-

N u m b e r of r e d

blood

cells p er

c u b i c m i l l i m e t e r of b lo o d .

R ainbow T ro u t

B rook T rout

D ate
D iet

1

L iver

Diet

1

L iver

M arch,

1 9 5 4 ...............

1,140,000

1,344,000

1,269,000

1,215,000

M arch,

19 5 5 . .

1,298,000

1,153,000

1,386,000

1,158,000

D I R E C T A ND I N D I R E C T SAVING D U E TO F E E D I N G
P E L L E T E D DRY M E A L S TO H A T C H E R Y REARED TROUT

I n 1 9 5 3 t h e f i r s t I v l i c h i g a n S t a t e t r o u t f o o d , D i e t 1, w a s f o r m u ­
la te d and pelleted.
resu lts

w ere

A fter

so f a v o r a b le

s e v e r a l m o n t h s of e x p e r i m e n t a t i o n t h e
th a t it w as a d o p te d by the M ic h ig a n D e ­

p a r t m e n t of C o n s e r v a t i o n a s a s t a n d a r d t r o u t p r o d u c t i o n d i e t e v e n
before
ies

experim ental te sts

w ere

w ere

com pleted.

Some

state fish h a t c h e r ­

s lo w in a d o p tin g the p e l l e t food on a p r o d u c ti o n s c a le , but

all w ithout ex ce p tio n a r e

now feeding p e lle ts,

re s u ltin g in lo w e re d

food c o s ts .
T able

20 p resen ts

utilized and pounds

of t r o u t p l a n t e d f o r e a c h y e a r

an d ending on F e b r u a r y
culated on a c a le n d a r
F i s h food e x p e n d itu re s
com piled.
tu res

the m a n n e r in w h ich t r o u t fo o d fu n d s w e r e

29, 1956.

year,

Pounds

s t a r t i n g in 1950

of t r o u t p l a n t e d a r e

cal­

e x p e n d itu re s on a fis c a l y e a r b a s is .

during

1955-56 have not b een com pletely

H o w e v e r , th e t r e n d up to th i s t i m e i n d i c a t e s th a t e x p e n d i ­

w ill n o t e x c e e d t h o s e of l a s t f i s c a l y e a r .

p lan ted fo r that y e a r a r e

co rrectly

P o u n d s of t r o u t

shown.

I t w i l l b e n o t e d ( T a b l e 21) t h a t , s i n c e t h e p e l l e t - f e e d i n g p r o ­
gram

s t a r t e d in 1953, f is h food e x p e n d itu re s

85

d e c r e a s e d and n u m b e r

86
T able

20.

The financial story
duction.

o f f i s h fu n d i n r e l a t i o n t o t r o u t p r o ­

Year

A ppro­
priation

A llot­
ment

Expen­
diture

P o u n d s of
T rout
P lanted

1950-51

$190,000

$182,715

$197,083

299,450

1951-52

200,000

200,562

178,751

282,641

1952-53

217,000

200,000

182,344

284,628

1953-54

200,000

183,800

146,896

297,774

1954-55

165,905

165,905

132,392

390,613

1955-56

150,000

150,000

1956-57

140,000

aTo F ebruary

--

2 9 , 1956.

72 , 9 7 0 a
--

417,495
--

87
Table

21,

P ro d u ctio n costs as
feeding re g im e .

c o m p a r e d t o t h e old a n d n e w t r o u t

$197,083

299,450

65£

1951-52

178,751

282,641

63

1952-53

182,344

284,628

64

P ellet F eeding P ro g ra m

Calcu-o *> ir
1 S3
S

1950-51

Trout
Planted

Cost
per
l b . of
T rout

-30

Year

E xpenditure
A ctual Food
C ost (pellets
and m e a t )

D iff e r encea

Started

1953-54

146,896

297,774

49

$190,575

$ 43,679

1954-55

132,392

390,613

33

249,992

117,600

417,495

267,196

194,226

1,105,882

$707,763

$355,505

72 , 9 7 0 b

1955-56

T o tal,
1953-56

$352,258

O ther e x ­
penditure s c

18,000
$337,505

a C alculated
\ o

c o s t a t 64£ m i n u s a c t u a l f o o d c o s t .

February

29,

1956.

CS a l a r y a n d e x p e n s e s a l l o t t e d t o i n v e s t i g a t o r f o r f o r m u l a t i n g
and t e s t in g d r y p e lle t d ie ts d u rin g the

3 -y ear period.

of p o u n d s o f t r o u t p l a n t e d i n c r e a s e d .
the

T h is is d i r e c t l y r e f l e c t e d in

c o s t p e r p o u n d of f i s h p r o d u c e d .
B efore

the p e lle t- f e e d in g p r o g r a m

c e n t s f o r f o o d to p r o d u c e

w a s a d o p t e d , i t c o s t 64

o n e p o u n d of t r o u t .

w e ig h t of t r o u t p l a n t e d d u r in g

the p e r i o d

W h e n the c o s t of t o t a l

1 9 5 3 t o 1 9 5 6 (th e p e l l e t -

f e e d i n g p e r i o d ) i s b a s e d o n t h e 6 4 - c e n t f o o d c o s t r e q u i r e d to r a i s e
o n e p o u n d of t r o u t b e f o r e

pellets

h a v e b e e n $ 7 0 7 ,7 6 3 to p r o d u c e

u s e d , total food c o s t s w ould

1 , 1 0 5 , 8 2 2 p o u n d s of t r o u t .

i t c o s t o n ly $ 3 5 2 ,2 5 8 to p r o d u c e
it c a n be d e fin ite ly

w ere

t h i s w e i g h t of t r o u t .

H owever,

T herefore,

s t a t e d t h a t a s a d i r e c t r e s u l t of t h e r e s e a r c h

d e s c r ib e d in this p a p e r

t h e M i c h i g a n D e p a r t m e n t of C o n s e r v a t i o n w a s

a b l e t o e f f e c t a s a v i n g i n f i s h f o o d e x p e n d i t u r e of $ 3 5 5 , 5 0 5 d u r i n g
a th r e e - y e a r period.
T h e i n d i r e c t s a v i n g b y u s e of p e l l e t s
vantage.

L e s s la b o r was

c o m p a r e d to m e a t s
cleaner.

Less

tro u t was m o re
in the

n e e d e d to p r e p a r e

and m ixed foods.

refrig erated

storage

was a lso a m a jo r a d ­
and feed pellets as

P onds and pond s c re e n s
space was needed.

w ere

G r o w t h of

r a p id and m o r e tr o u t r e a c h e d le g a l s iz e f o r planting

second y e a r that f o r m e r ly p o ssible.

This m e a n s f e w e r tr o u t

h a d to b e c a r r i e d o v e r into the t h i r d y e a r , m a k in g m o r e pond s p a c e
available fo r

s m a lle r fish.

PO SSIB LE V ALUE OF P E L L E T E D

FO O D AS A

M ED IU M F O R DISPENSING M ED IC A TIO N
TO TROUT

In M ichigan, and in general w h e re v e r tro u t a re
h a tc h e ry conditions, a d is e a s e

re a r e d under

of b a c t e r i a l o r i g i n , A e r o m o n a s

sal-

m onicida

(com m only know n a s fu ru n cu lo sis) has caused se rio u s

dem ics.

It h a s b e e n s ta te d

(M cC raw ,

19 52 ) t h a t no f i s h d i s e a s e i s

to b e f e a r e d m o r e b y the h a t c h e r y m a n t h a n f u r u n c u l o s i s .
v ie w p u b li s h e d b y the

the v a r io u s l i t e r a t u r e

ease

s e v e re ly in c e rta in

in o th e rs .

H is r e ­

U n ite d S t a t e s D e p a r t m e n t of I n t e r i o r p r e s e n t s

inform ation g ath ered fro m
appears

epi­

to a c t m o r e

sources.

species

The d i s ­

of t r o u t t h a n

In M ich ig an , b r o w n tr o u t, S alm o t r u t t a , a r e

m ore

sus­

cep tib le th a n o t h e r s , a n d b ro o k tro u t, S alvelinus f o n ti n a li s , a r e next.
V arious in v e stig a to rs

have d e te r m in e d that m any o th e r

fis h c o n tra c t fu ru n c u lo sis b ut epidem ic
quently th a n in b ro w n o r b ro o k trout.
u s e d is to f e e d a m i x t u r e
the d aily fo o d r a tio n .

status

was re a c h e d l e s s f r e ­

A m e t h o d of t r e a t m e n t o f t e n

of s u l f a g u a n a d i n e a n d s u l f a m e r a z i n e

Two h u n d re d g r a m s

s u l f a g u a n a d i n e a n d two p a r t s

with

of a m i x t u r e of o n e p a r t

of s u l f a m e r a z i n e w h e n m i x e d w i t h 100

p o u n d s o f r a w m e a t i s f e d f o r a c e r t a i n n u m b e r of d a y s
o n the

s p e c i e s of

s e v e r i t y of d i s e a s e p r e s e n t .

89

depending

90
In h a t c h e r ie s

w h e r e f u r u n c u l o s i s f r e q u e n t l y r e o c c u r s , it is

o f t e n n e c e s s a r y t o f e e d s u c c e s s i v e l y h i g h e r l e v e l s of s u l f a d r u g s
fo r adequate

treatm en t or

s a f e to a s s u m e

control.

th a t the p a r t i c u l a r

B e c a u s e of t h i s i t m i g h t b e
s t r a i n of p a t h o g e n w a s b e c o m i n g

s o m e w h a t r e s i s t a n t t o t h e d r u g a n d t h a t if t h e l e v e l s of d r u g s a d ­
m inistered

c o n t i n u e d to b e i n c r e a s e d , th e h o s t c o u ld b e a d v e r s e l y

affected befo re

the d ru g a c t e d on the p ath o g en .

It s e e m s a s though

m e d i c a m e n t s of m i l d c h e m i c a l a n d p h y s i o l o g i c a l n a t u r e , a d a p t e d to
continuous feeding,
indirectly;

could offer a m e a n s fo r

that is, by reducing

c o n tro llin g this

disease

t h e n u m b e r s of o r g a n i s m s of l o w

p a t h o g e n ic i ty i n the i n t e s t i n a l t r a c t .

In o t h e r w o r d s ,

"cleaning up"

t h e i n t e s t i n a l t r a c t m a y b e a l l t h e p h a r m a c o t h e r a p y n e e d e d to p r e ­
vent a serio u s

o u t b r e a k of f u r u n c u l o s i s .

I n o r d e r to t e s t t h i s h y p o t h e s i s , i t w a s n e c e s s a r y f i r s t to
s e l e c t a d r u g o r g r o u p of d r u g s

t h a t c o u l d b e a p p l i e d to c o n t i n u o u s

feeding w ithout a d v e r s e l y affecting
In in v e stig a tio n s

the a n i m a l in g e n e r a l .

c o n d u c te d w ith w a r m - b lo o d e d a n im a ls it

w a s f o u n d t h a t a g r o u p of d r u g s , a n t i b i o t i c s , c o u l d b e c o n t i n u o u s l y
fe d effectively, and that b en efit was
T h e y w e r e f o u n d to:
activity,

(2) h a v e

derived fro m

(1) b e d i f f e r e n t i n

considerable

this p ra c tic e .

stru ctu re and biochem ical

v a ria n c e in s p e c tra ,

(3) b e c o m p a t i b l e
1

t o o t h e r d i e t i n g r e d i e n t s w h e n m i x e d t o g e t h e r , a n d (4) b e e s s e n t i a l l y ^

91
nontoxic
causing

e v e n in e x c e s s q u a n titie s .

B esides

su b clin ical d is e a s e s , antibiotics

o rg an ism s

w hich co m p e te

s u p p r e s s i o n of o r g a n i s m s

w o r k to s u p p r e s s i n t e s t i n a l

w i t h a n a n i m a l f o r v i t a m i n s i n th e f o o d

i t e a t s a n d t h i n s t h e w a l l s of t h e i n t e s t i n e p e r m i t t i n g b e t t e r a b s o r p ­
t i o n of v i t a m i n s

and n utrients

a p p e a r e d to p r o v i d e
sary

in the body.

T h i s g r o u p of d r u g s

the p h y s i c a l a n d c h e m i c a l q u a lif ic a tio n s n e c e s ­

to t e s t t h e h y p o t h e s i s p r e v i o u s l y d e s c r i b e d .
R e c e n t l y a n e w t y p e of t r o u t f o o d w a s a d o p t e d b y t h e s t a t e

of M i c h i g a n .
various
for

I t c o n s i s t s o f a n i m a l a n d v e g e t a b l e m e a l s p e l l e t e d in

sizes.

T r o u t food in th is f o r m

t h e i n t r o d u c t i o n of m e d i c a m e n t s

pellet fo rm

could be

thus in s u rin g

stored for

a n adequate

w ith o t h e r d ie t in g r e d i e n t s
diets

could be m o re

offers

se v e ra l advantages,

to t r o u t .

M e d i c a te d d ie ts in

se v e ra l m onths at each hatchery,

supply at a ll tim e s .
could be

D a i l y m i x i n g of d r u g s

elim inated.

D ru g s in d r y m e a l

uniform ly distributed, th ereby in c re asin g

control

of a m o u n t s f e d .
In 1953, a b r o a d

s p e c tru m antibiotic, au re o m y c in ,

w ith d ry m e a l s a n d p ellete d .

An anim al feed

10 g r a m s of c h l o r t e t r a c y c l i n e ( A u r e o m y c i n ,

was m ix ed

s u p p le m e n t containing

t r a d e m a r k of t h e A m e r ­

ic an C yanam id

C o m p a n y f o r the a n tib io tic

c h lo rtetra cy clin e) p e r pound

was used a t a

1 p e rc e n t level, furnishing

200 g r a m s

a c t i v i t y p e r to n of f i n i s h e d fe e d .

aureom ycin

T his le v e l w as b a s e d on that found

92
to b e c o m p a t i b l e

to p o u l t r y f e e d s .

This d ie t was fe d f o r a s ix -m o n th

p e r i o d to r a i n b o w a n d b r o o k t r o u t f i n g e r l i n g s .

Being a pilot e x p e r i­

m e n t , it w a s c o n d u c t e d s o le ly to d e t e r m i n e the g r o s s
m y c in a s a tro u t food additive.
was not p o ssib le fro m

To f u r t h e r

e x p e r i m e n t to a t t r i b u t e a n y

to t h e p r e s e n c e of t h e d r u g i n t h e d i e t .

t e s t the h y p o th e sis

f o r the d i s e a s e

A ll t r o u t r e a c t e d f a v o r a b ly , a n d it

t h e d e s i g n of t h i s

advantages o r disadvantages

e f f e c t of a u r e o ­

to a p p e a r .

it was n e c e s s a r y ,

s e c o n d l y , to w a i t

I t w a s f e l t t h a t if t r o u t c o n t r a c t e d f u r u n ­

c u lo s is in the u su a l m a n n e r r a t h e r than through m e c h a n ic a l in jectio n
of t h e d i s e a s e - p r o d u c i n g o r g a n i s m , t h e c o n d i t i o n w o u l d b e m o r e
resentative

of t h a t o c c u r r i n g

Since it w as

furunculosis
w aters,
tim e

during n o rm a l h a tc h e r y - tr o u t production.

su sp e c te d that A e ro m o n a s

p r e s e n t in h a tc h e ry w ater

s a lm o n ic id a is co n sta n tly

supplies w h ere

o c c u r and sin ce it is p o s sib le

e ith e r the f is h a r e

m ore

r e p e a t e d o u t b r e a k s of
to r e a r

tro u t in such

p h y sio lo g ic a lly r e s i s t a n t at one

th a n a n o t h e r o r the p a th o g e n is not a b le

s tru c tiv e f o rc e a t all tim e s

rep­

to e x e r t i t s f u l l d e ­

d u e to v a r i a t i o n s i n e n v i r o n m e n t a l c o n ­

d i t i o n s a n d p a r t i c u l a r l y to v a r i a t i o n s i n i n t e r c u r r e n t s u b c l i n i c a l i n ­
fections.

T h e r e f o r e , it m i g h t be e x p e c te d th a t in je c tin g f i s h w ith

p a t h o g e n s to p r o d u c e a n a r t i f i c i a l
le ss

valid than those f r o m fish

contam ination.

e p id e m ic w ould p ro d u c e r e s u l t s

contracting fu ru n cu lo sis fro m

endem ic

93
Since it w as a l r e a d y d e m o n s t r a te d that n o r m a l rain b o w and
brook trout w ere

n o t a p p r e c i a b l y a f f e c t e d b y c o n t i n u o u s f e e d i n g of

a u r e o m y c in a t a c e r t a i n le v e l, a d ie t containing this d ru g was kept
i n s t o c k r e a d y f o r i n s t a n t u s e i n Hie e v e n t f u r u n c u l o s i s a p p e a r e d i n
i
a n y g r o u p of t r o u t .
A n o p p o r t u n i t y to t e s t t h e d i s e a s e - p r e v e n t i o n p r o p e r t i e s of
a u r e o m y c i n w as p r e s e n t e d in S e p te m b e r,

1955.

F urunculosis

d e t e c t e d i n a g r o u p of t w o - y e a r - o l d b r o o k t r o u t .
b e e n r e a r e d in h a tc h e ry c o n c re te tanks
s u s ta in e d o n a n a l l - d r y - m e a l diet.

since

was

These trout had

hatching and had b een

I m m e d i a t e l y u p o n d e t e c t i o n of

the d i s e a s e , a ll tr o u t w e re counted.

O ne-half,

106 i n n u m b e r , w e r e

p l a c e d i n a n a d j a c e n t t a n k , a n d o n e - h a l f w e r e a l l o w e d to r e m a i n i n
the o r ig in a l tan k .
m ycin p e r

A p e l l e t e d d i e t c o n t a in in g 200 g r a m s

t o n of f e e d w a s

u s e d f o r the m e d ic a tio n .

of a u r e o ­

T h e g r o u p of

10 6 i n t h e o r i g i n a l t a n k w e r e f e d t h e m e d i c a t e d d i e t i n a m o u n t s
e q u a l t o 1 . 7 p e r c e n t of b o d y w e i g h t p e r d a y , a n d t h e o t h e r g r o u p
c o n t i n u e d to r e c e i v e
noted a t

the p e l l e t e d d ie t fe d b e f o r e

1. 7 p e r c e n t of b o d y w e i g h t p e r d a y .

the d i s e a s e w as

Since a p e l le te d m e d i ­

c a t e d d i e t w a s o n h a n d , th e e x p e r i m e n t w a s i n e f f e c t two h o u r s a f t e r
d e te c tin g the d is e a s e .
em phasis

B oth g ro u p s

w as placed on m o rtality

w e re w eighed p e rio d ic a lly but
r a t h e r than g ro w th in c r e a s e s .

94
D u rin g the c o u r s e
M arch,

1956, b o th lo ts

fertilized

eggs

o f t h e e x p e r i m e n t , S e p t e m b e r , 1 9 5 5 , to

of f i s h w e r e a r t i f i c i a l l y

i n c u b a t e d i n w a t e r a t 42° F .

s p a w n e d a n d th e

At th e t i m e of s p a w n -

ing the m e d i c a t e d g r o u p h a d b e e n f e d a u r e o m y c i n co n tin u o u sly fo r
two m o n t h s .
is

show n in
As

T h e t o t a l n u m b e r of t r o u t w h i c h d i e d f r o m
T a b le 22.

show n in Table

t h e n u m b e r of f i s h
it a p p e a rs

each group

22, t h e r e

surviving

w as a wide d iffe re n c e b e tw e e n

in the tw o g r o u p s .

From

these

results

t h a t a u r e o m y c i n c o n t r i b u t e d to t h e w e l l - b e i n g of t h e f i s h

a fflic te d w ith f u r u n c u lo s is .

Since the only k now n v a r i a b l e p r e s e n t

i n t h e d i e t w a s t h e l e v e l of a u r e o m y c i n f e d , i t i s n e c e s s a r y to c o n ­
clude th a t th e r e

w a s a v e r y goo d c h a n c e th a t the m e d ic a t e d d iet

e i t h e r a b e t t e d r e c o v e r y of t h o s e f i s h a l r e a d y a f f l i c t e d a n d / o r
as a preventive

m easure

of b a c t e r i a m u l t i p l i c a t i o n .
groups w ere
to r e s u l t s

in th o s e f i s h n o t y e t u n d e r th e in flu e n c e
S in ce , d u rin g this p e rio d , f is h in both

s p a w n e d , a p o r t i o n of m o r t a l i t y m u s t b e c o n t r i b u t e d

of r o u g h h a n d l i n g n e c e s s a r y

during this o p eratio n .

e v e r , b o th g ro u p s w e r e h an d led in a s im i la r m a n n e r;
is

u n lik e ly th a t s u c h a w ide d iffe re n c e

to sp aw n in g o p e r a t io n s a lo n e .
both g ro u p s

served

are

in m o r ta lity

How­

th e re fo re , it

o c c u r r e d due

D a t a p e r t a i n i n g t o t h e p r o g e n y of

i n c l u d e d o n l y t o s h o w t h a t (1) e g g p r o d u c t i o n a n d

f e r t i l i z a t i o n is p o s s ib le in f i s h

su fferin g f r o m fu ru n c u lo s is , and

95
T ab le 22.

F u n c t i o n of a u r e o m y c i n in b r o o k t r o u t d i e t s .

M edicated

D iet

N onm edicated

Diet

D ate
M ortality

T o ta l No.

M ortality

T o ta l No.

T o ta l N u m b e r at S tart
106
B efore

106

Spaw ning

S e p te m b e r 30,
19 5 5 . . . . .

5

101

5

101

O c to b e r 31,
1.955 ...............

8

93

5

96

N o v e m b e r 18,
19 5 5 ...............

5

88

34

62

A f t e r Spaw ning
N o v e m b e r 30,
19 5 5 ...............

1

87

14

48

De c e m b e r 31,
1955 ...............

9

78

18

30

31,
...............

11

67

4

26

F e b r u a r y 29,
1 9 5 6 ...............

9

60

4

22

T otal n u m b er
up to F e b r u ­
a r y 2 9 , 1956

48

60

84

22

T otal p ercen t
m ortality . .

43

January
1956

P e r c e n t of e g g s
hatched . . .

79.2

57.5

23.1

96
(2) c o n t i n u o u s m e d i c a t i o n b y f e e d i n g a u r e o m y c i n f o r t w o m o n t h s
before

spaw ning an d u n d e r the co n d itio n s d e s c r ib e d above does not

ad v ersely affect fertiliz atio n and hatchability.

Progeny are

currently

b e i n g r e a r e d o n a m e d i c a t e d a n d n o n m e d i c a t e d d i e t to c o r r e s p o n d
w ith the d ie t r e c e i v e d by the p a r e n t fis h .
to f e e d th e p r o g e n y a s

w ell a s

i n a n a t t e m p t to d e t e r m i n e

It i s p l a n n e d t o c o n t i n u e

the p a r e n t f i s h th is m e d i c a t e d d ie t

t h e e f f e c t of a u r e o m y c i n o n r e p r o d u c t i o n

when fed fo r longer perio d s.

There

g r o u p s w ill c o n t r a c t f u r u n c u lo s is

is a ls o a good ch a n c e that a ll

a g a i n d u rin g the n e x t y e a r w hich,

if i t t a k e s p l a c e , w i l l p r o v i d e a n e x c e l l e n t o p p o r t u n i t y to t e s t t h e
v a l i d i t y of t h e

ex p erim en t ju st described.

It m u s t b e p o in te d out th a t the r e s u l t s
b a s e d on only one e x p e r i m e n t .

described here are

F u r t h e r in v e stig a tio n is n e c e s s a r y

t o d e f i n i t e l y p r o v e t h e v a l u e of a n t i b i o t i c s a s a m e a n s f o r p r e v e n t i n g
d iseases

in h a t c h e r y - r e a r e d tro u t.

DISCUSSION

D u e t o t h e b a s i c n a t u r e of t h e s t u d i e s r e p o r t e d h e r e i n , i t
was n e c e s s a ry
conform

to u s e

certain experim ental procedures

w ith m ethods u su a lly used.

t h e m a n n e r of f o r m u l a t i n g

w h i c h do n o t

An im p o r ta n t d iffe re n c e was

the f i r s t d ie t fo r n u tritio n a l stu d ie s.

I n s t e a d of f o r m u l a t i n g a d i e t s o l e l y f o r i t s n u t r i t i o n a l q u a l i t y , i t
was n e c e s s a ry

to p l a c e g r e a t e r

and p e rfo rm a n c e

em phasis

on pelleting p ro p e rtie s

of t h e p e l l e t i n a w a t e r m e d i u m .

T h e e a r l i e s t e x p e r i m e n t s r e p o r t e d in this p a p e r w e r e c o n ­
d u cted w ith

tr o u t w hose diet, b e fo re p e lle t feeding

of r e l a t i v e l y

soft m e a t diets.

feeding

started , consisted

It w a s fo u n d th a t th e t r a n s i t i o n f r o m

s o f t m e a t d i e t s to f e e d i n g h a r d p e l l e t d i e t s r e q u i r e d a n a d ­

j u s t m e n t p e r i o d of s e v e r a l w e e k s .
rainbow tro u t m ay
From

the

This a d ju stm e n t p e rio d for

extend o v e r fo u r

experim ents

weeks.

co n d u c te d , it could not be d e m o n s t r a t e d

c o n c l u s i v e l y t h a t r a i n b o w t r o u t p r e f e r o n e p e l l e t s i z e m o re t h a n
another.

Trout a re

food but a r e

a b l e to i n g e s t l a r g e p a r t i c l e s

r e l u c t a n t to i n g e s t l a r g e p a r t i c l e s

of s o f t p l i a b l e

of c o a r s e f o o d w h ic h

d o e s not c r u s h e a s ily w h en m o v e d th ro u g h the p h a ry n g e a l a r e a .
physical p ro p e rtie s

of t r o u t

foods

n e e d to b e i n v e s t i g a t e d f u r t h e r .

97

The

98
There

is m u c h r o o m f o r im p r o v e m e n t.

during th e se
ribbons

or

experim ents

P e rs o n a l observations

made

i n d i c a t e d th a t a d r y d ie t in the f o r m

s h o r t tu b e s w ould be m o r e

of

su ita b le th an solid p e lle ts .

E x p e r i m e n t a t i o n d i r e c t e d t o w a r d d e v e l o p i n g d i f f e r e n t f o r m s of d r y
diets n eeds
acceptance

to b e

c a r r i e d out n ot only f r o m

but fro m

rate

of d i g e s t i o n a s w e l l .

The ta b u la r data p o rtra y b e tte r
the

experim ents

t h e s t a n d p o i n t of t r o u t

conducted.

t h a n w o r d s t h e r e s u l t s of

T o a t t e m p t a n e v a l u a t i o n of i n d i v i d u a l

d i e t a r y c o n s t i t u e n t s o n t h e b a s i s of t h e d a t a p r e s e n t e d h e r e
be unw ise.

A l l of t h e m a r e

and all w a rra n t fu rth e r

acceptable as

would

tro u t diet com ponents

study w hen c o n s id e rin g

t h e i r r e l a t i o n s h i p to

e a c h o th e r an d th e ir re la tiv e n u tritio n a l value a s food fo r tro u t.
F rom

T able

7 it is

s e e n t h a t D i e t 1, w h e n f e d c o n c u r r e n t l y

to t w o g r o u p s of r a i n b o w t r o u t , p r o d u c e d n e a r l y i d e n t i c a l r e s u l t s i n
all conditions

shown.

C o n v ersio n fa c to rs fo r all diets a r e

in c lu d in g the r a w b eef l i v e r c o n tro l.
feeding was

em ployed throughout th e se

sion f a c to rs

w ould be

U sually g r e a te r

poses.

N evertheless,

of

ex p erim en ts, hig h er co n v er­

v o l u m e s of f o o d a r e f e d f o r p r o d u c t i o n p u r ­

it should be pointed out th a t w hen r a w m e a ts

c a re fu lly fed, a c o n v e rsio n fa c to rs

This, how ever, is

Since a r e s t r i c t e d f o r m

expected w hen tro u t a r e fed on a production

scale.

are

sm all,

a s low a s

3.0 c a n b e a t ta in e d .

r e f l e c t e d i n a s l o w e r g r o w t h r a t e p e r u n i t of t i m e .

99
W hen fed on a production b a sis
sion f a c to rs
(Table

17) a n d
D iets

to

w ere

to b r o o k t r o u t , p e l l e t e d f o o d c o n v e r ­

o n e - h a l f t h o s e of r a w

m eat conversion facto rs

still p r o d u c e d a g r e a t p e r c e n t g a in in w eight.

1 an d 2 a n d D iets

diet v a ria b le s .

plete and u n reliab le

D iets
data.

3 and 4 ca n be c o m p a re d in r e s p e c t

3 a n d 7 m u s t b e e l i m i n a t e d d u e to i n c o m ­
C ircum stances

b e y o n d t h e c o n t r o l of th e

in v e s t ig a t o r n e c e s s i t a t e d changing p r o c e d u r e s
the

experim ent.

t w o - t h i r d s way th r o u g h

T h e d a t a a r e p r e s e n t e d o n l y to s h o w t h a t t r o u t

c a n be r e a r e d f o r tw en ty -e ig h t w eeks on th ese diets.
The d ietary
used.

v a ria b le s in D iets

D i e t 2, c o n ta in in g b r e w e r s

1

yeast

and

2 a r e th e t y p e s of y e a s t

(T a b le 4), o u t p e r f o r m e d

D iet 1 co n tain in g to r u la y e a s t in a ll r e s p e c t s , b u t r e c o r d e d lo s s e s .
In both g ro u p s

receiving

D ie t 2 the r e c o r d e d l o s s e s w e r e a p p r o x i ­

m a t e l y d o u b l e t h o s e of g r o u p s

receiving

p e r c e n t m o r t a l i t y f o r the g r o u p s
G roups fed
all
diets

respects,

D i e t 1.

B u t, the to ta l

r e c e i v i n g the two d ie ts i s r e v e r s e d .

D i e t s 3 a n d 4 w e r e v e r y s i m i l a r to e a c h o t h e r in

w ith D ie t 3 p ro d u c in g s o m e w h a t b e t t e r r e s u l t s .

containing b r e w e r s

y e a s t a t a 5 p e rc e n t level

All

showed g r e a te r

g a in s a t lo w e r c o s ts , alth o u g h w ith h ig h e r m o r ta lity , th a n th o se c o n ­
tain in g

5 p e rc e n t to ru la yeast.

O n t h e b a s i s of t h e s e

an d c o n s id e rin g a ll f a c t o r s , both y e a s ts
5 p e r c e n t le v e l f o r p e llete d tro u t diets.

can

be

experim ents
r e c o m m e n d e d ata

W hen evaluating

the d ie ts o n the b a s i s

of l e g a l - s i z e d t r o u t

p r o d u c e d d u r i n g a g i v e n t i m e , D i e t 6 m u s t b e r a t e d h i g h e r t h a n th e
rest.

W hen the l e g a l - s i z e d

considered for

t r o u t p r o d u c e d in p e r c e n t by w eig h t is

e a c h diet, all diets w ere about equal.

le g a l-s iz e d trout produced by num ber
produced a low er num ber

(Table

B u t , w h e n th e

is c o n s i d e r e d , D ie ts 3 a n d 4

10).

D iets

6, 8, 1, a n d 2, i n t h a t

o r d e r , p r o d u c e d t h e h i g h e s t p e r c e n t a g e of l e g a l - s i z e d f i s h .
corded lo sse s

in g ro u p s

r e c e i v i n g D ie t 1 w e r e the lo w e s t, a n d th o s e

r e c e i v i n g D ie t 4 the h ig h e s t .

From

the d a ta p r e s e n t e d it is c o n ­

cluded th at p e l le t- m e a t co m binations as fed during these
m ents

w ill c o n s is te n tly

Re­

experi­

grow approxim ately as m any le g a l-siz e d

tr o u t as a ra w beef liv e r diet during

c o m p a ra b le p e rio d s at a food

c o s t o n e - t h i r d of t h a t of r a w l i v e r d i e t s a n d w i t h l e s s l a b o r .
It is alw ay s

a problem

when la rg e

n u m b e r s of a n i m a l s

are

u s e d f o r e x p e r i m e n t a t i o n to o b t a i n s i z e u n i f o r m i t y b e t w e e n i n d i v i d ­
uals.
D iets

F rom

9 it is o b v io u s th a t the u n a c c o u n ta b le l o s s e s f o r

1, 4, a n d 6 f a r o u t n u m b e r t h e r e c o r d e d l o s s e s .

and recalling
lo sses

Table

are

At f i r s t glance

the m e t h o d s u s e d , one m i g h t c o n c lu d e th a t a ll the high

due to c a n n i b a l i s m .

w ill r e v e a l th a t th is

H ow ever, m o re

c a n n o t b e the only r e a s o n .

careful analysis
All t r o u t f e d the

s a m e d ie t w e r e t r e a t e d i n a n id e n tic a l m a n n e r , an d the only d i f f e r ­
ence b etw ee n dual g ro u p s was d ietary .

T h e r e w a s a w ide d if f e r e n c e

101
(Table

9) i n t h e u n a c c o u n t a b l e l o s s e s

( D i e t 4) a s w e l l a s

different diets.

in g r o u p s f e d the s a m e diet
G ross

o b s e r v a t i o n s d u r in g the

e x p e rim e n ta l p e rio d re v e a le d that co n sid erab le

"nipping"

on in a ll but the r a w b eef liv e r c o n tro l group.
c o n fin e d to the d o r s a l an d c a u d a l f in a r e a s .
becam e
w ere
dition

so

left

severe
as

that

the

independent

resem bled

a

w hole

fin

rods.

serious

To

case

was
the

The

"nipping"

was

In so m e in s ta n c e s it
rem oved

casual

of f i n

w a s going

rot.

or

fin-rays

observer
This

the

con­

"nipping" ten­

d e n c y a p p e a r s to b e m o r e

characteristic

brook trout.

w as o p e r a t i n g in the c o n tro l g r o u p w hich

Some facto r

re d u c e d this tendency.

W h e th e r d ie ta r y o r o th e r w is e is not known.

It s h o u l d b e r e c a l l e d t h a t t h e s e
crete

o f r a i n b o w t r o u t t h a n of

rainbow tro u t w ere

r e a r e d in c o n ­

t a n k s of r a t h e r l i m i t e d a r e a .
T h e c o n d i t i o n f a c t o r of r a i n b o w t r o u t a l l o w s

som e insight as

the n u t r i t i o n i s t

to t h e r e l a t i o n s h i p b e t w e e n w e i g h t a n d l e n g t h .

Among

o t h e r t h i n g s , n u m e r i c a l d i f f e r e n c e s i n t h i s f a c t o r c a n b e d u e to d i e ­
tary factors.

In Table

12 i t w a s

show n that D iet 8 (control) p r o ­

d u ced tro u t s h o r te r b ut a p p ro x im a te ly as heavy as those f r o m
la rg e - sized groups fed pellet diets.

From

the e q u a tio n

the

show n, it

c a n b e d e m o n s t r a t e d th a t w h en t h e r e is a w e ig h t i n c r e a s e w ithout
le n g th i n c r e a s e the
that,

c o n d itio n f a c t o r w ill i n c r e a s e . .

s i n c e t h e c o n d i t i o n f a c t o r s of t r o u t f e d p e l l e t s

This then m e a n s
(Table

13) w e r e

102
le ss

t h a n t h a t of t h e

in le n g th m o r e

c o n t r o l , t h e t r o u t fed. p e l l e t s w e r e i n c r e a s i n g

th a n m e a t-fe d . tr o u t , but w ith l e s s

in c re a s e in b re a d th

and. d e p t h o f b o d y d i m e n s i o n s .
U s u a l l y , g a i n i n l e n g t h o r h e i g h t i s a s s o c i a t e d w i t h g r o w t h of
p ro tein tissue,

w hereas

fa t deposition a s
sis

d e p th a n d b r e a d t h g a in s a r e a s s o c i a t e d with

w ell a s p r o te in tis s u e f o r m a tio n .

to e s t a b l i s h f a t - t o - p r o t e i n r a t i o

was

C hem ical a n a ly ­

n o t c a r r i e d out ; t h e r e f o r e ,

it c a n n o t be d e f in ite ly c o n c lu d e d th a t p e l le te d d ie ts will p r o d u c e
m o re p rotein tissu es

th a n a r a w b eef liv e r diet.

It a p p e a r s , h o w ­

e v e r , th a t w ith m o r e

e x p e r i m e n t a t i o n a d r y p e lle te d diet could be

f o r m u l a t e d t o p r o d u c e , up to a r e a s o n a b l e p o i n t , t h e d e s i r e d l e v e l
of f a t a n d p r o t e i n r a t i o

in tro u t.

C ondition f a c to r s fo r
sam e

age a re

and large

show n in T ab le

groups a re

to the a v e r a g e

s m a l l , m e d i u m , a n d l a r g e t r o u t of t h e
H ere again facto rs

group.

t h e w e l l - b e i n g of t r o u t i n M i c h i g a n b y r e d b l o o d

cell counts has been a co m m o n p ra c tic e .
vegetable and an im al m e a ls
diet a d ie ta ry a n em ia
experim ents
binations

in the s m a ll

h i g h e r f o r D i e t 8 th a n the o t h e r s , b u t eq u al

in m e d iu m

D eterm ining

14.

B efore

w ere fed as a la rg e

developed in tro u t.

19 5 3 , w h e n d r y
p o r t i o n of t h e t o t a l

The resu lts

of c u r r e n t

s h o w th a t d r y v e g e t a b l e a n d a n i m a l m e a l s , in the c o m ­

u s e d d u rin g this

e x p e r i m e n t , will not d e v e lo p this a n e m ic

103
condition in tro u t.
ered as

E rythrocyte

a n i n d i c a t i o n of t h e

in T ables

17 a n d

n u m b e r s b e lo w 900,000 a r e

s t a r t of a n a n e m i c

As

shown

1 8, r a i n b o w a n d b r o o k t r o u t f e d a p e l l e t e d d r y d i e t

p r o d u c e d n u m b e r s of r e d blo o d c e lls

c o m p a r a b l e t o t h o s e of t r o u t

fed ra w beef liv e r and g r e a te r n u m b ers
and m elts.

condition.

consid­

th a n those fed p o rk liv e r

At no point th ro u g h o u t this e x p e r im e n t and f r o m

tion tro u t in o th e r h a tc h e r ie s w as it p o ssib le
to b e d u e to p e l l e t e d d r y f o o d s

produc­

to d e m o n s t r a t e a n e m i a

e v e n w h en fe d one y e a r w ithout ra w

m e a t supplem entation.
To d e m o n stra te

t h e p r a c t i c a l a p p l i c a t i o n of t h e p e l l e t e d d i e t s

te s te d , the p e r f o r m a n c e
is

shown in

Tables

of D i e t 1 w h e n c o m p a r e d to a m e a t c o n t r o l

15 a n d 16.

usual production re c o rd s
M ichigan.

As

is not a l w a y s

show n, fe e d in g r a w m e a t once e v e ry fo u r o r five days
necessary.

than a ra w

b e tw e e n the g ro u p s
From

the

k e p t b y s ta te f i s h h a t c h e r y p e r s o n n e l in

A ll t h r e e d ie t c o m b in a tio n s will p ro d u c e

brook tro u t at a higher ra te
of f i s h r e a r e d

T hese data w ere gained f r o m

these

of g a i n a n d a t a l o w e r c o s t p e r p o u n d

m e a t diet.

The d if f e r e n c e in m o r t a l i t y

w as negligible.
experim ents

w ill g ro w at a n o r m a l r a te

it c a n b e co n c lu d e d that b ro o k tro u t

when fed a p ellete d diet p erio d ically

s u p p l e m e n t e d w i t h m e a t f o r a p e r i o d of t w e n t y - e i g h t w e e k s a n d
th a t w h en n e c e s s a r y m e a t s u p p le m e n ta tio n c a n be w ithheld fo r as

104

long a s

three

weeks

w i t h o u t a d v e r s e l y a f f e c t i n g t h e r a t e of g r o w t h

an d w ithout in c r e a s in g

m ortality.

A d irec t and indirect
to h a t c h e r y - r e a r e d

s a v i n g d u e to f e e d i n g p e l l e t e d d r y m e a l s

tr o u t c a n be d e fin ite ly d e m o n s t r a te d .

p e l l e t s i n s t e a d of r a w m e a t s

has

p e r p o u n d of f i s h r a i s e d , f r o m

T h e u s e of

e f f e c t e d a r e d u c t i o n of f o o d c o s t s

64 c e n t s

tro u t p ro d u ce d on a state-w id e b a sis.

to 18 c e n t s p e r p o u n d of
It c a n be

stated that as a

d i r e c t r e s u l t of t h e r e s e a r c h d e s c r i b e d i n t h i s p a p e r , t h e M i c h i g a n
D e p a r t m e n t of C o n s e r v a t i o n w a s a b l e to e f f e c t a d i r e c t s a v i n g i n
f i s h f o o d e x p e n d i t u r e s of $ 3 5 5 ,5 0 5 d u r i n g th e t h r e e - y e a r p e r i o d .
S tated in a n o t h e r way,
percent less

money

60 p e r c e n t m o r e

s p e n t f o r f i s h food.

t r o u t w e r e p r o d u c e d o n 40

SUM M ARY AND CONCLUSIONS

In fe e d in g t r i a l s

c o n d u c te d w ith ra in b o w and b ro o k tr o u t s e v ­

e r a l p e l l e t e d d i e t s w e r e f o r m u l a t e d a n d t e s t e d , the r e s u l t s of w hich
have been p resen te d .
T he study w as

d i r e c t e d t o w a r d t h e u l t i m a t e g o a l of d e v e l o p -

p r a c t i c a l p e l l e t e d d r y d i e t s w h i c h c o u l d b e f e d to t r o u t t o p r o ­
duce

s t r o n g , h e a l t h y , l e g a l - s i z e d f i s h in the s h o r t e s t t i m e p o s s i b le

a n d e l i m i n a t e the n e e d f o r r a w m e a t m i x t u r e s a s m u c h a s p o s sib le .
L arge

n u m b e r s of t r o u t w e r e

both on an e x p erim en tal
F rom
1.
1 through

used as

experim ental anim als

s c a le and on a p ro d u c tio n sc a le .

th e d a ta o b ta in e d , the fo llo w in g c o n c lu s io n s w e r e d ra w n :

T h e b i n d i n g p r o p e r t i e s of f e e d c o n s t i t u e n t s
7 w ere

suitable fo r p e lle t production.

r e m a i n i n t a c t in p e l l e t f o r m f o r a s long a s

u sed fo r D iets

T h ese com binations

eight m in u te s w hen p la c e d

in a w a te r m e d iu m .
2.
trout req u ire

A s d e t e r m i n e d b y l o s s a n d g a i n of b o d y w e i g h t , r a i n b o w
one to two w e e k s

d ie t to a h a r d p e l l e t e d diet.

to a d j u s t f r o m

a re la tiv e ly soft m e a t

R a in b o w t r o u t lo s e w eight durin g the

a d j u s t m e n t p e r i o d b u t b e g i n to r e g a i n i t a f t e r the f i r s t tw o w e e k s
of p e l l e t f e e d i n g .

105

106
3.
lets

3 /l6 ,

R ainbow tro u t av era g in g
1 /8 , and 3/32

evidence fr o m

this

4. 5 i n c h e s i n l e n g t h w i l l e a t p e l ­

i n c h i n d i a m e t e r a n d 1/ 4

inch long.

s t u d y i s i n a d e q u a t e to d e m o n s t r a t e

The

d efinitely that

a n y s i z e p e l l e t i s p r e f e r r e d b y r a i n b o w t r o u t 4.5 i n c h e s l o n g .
4.

D r y p e l l e t d i e t s c a n b e f e d a t l e v e l s o n e - h a l f to f i v e -

eighths lo w e r than th o se re c o m m e n d e d fo r ra w m e a t m ix tu re s w ith­
out red u cin g tr o u t grow th r a te s ,
5.

T h e d if f e r e n c e b e tw e e n D ie t 1 (containing to r u la yeast)

and D iet 2 (containing b r e w e r s
(control) w as
an d in the

statistically

y e a s t) an d b e tw e e n D iet 2 and D iet 8

significant.

com binations used, b re w e rs

U n d e r the c o n d itio n s

described

y e a s t w a s s u p e r i o r to t o r u l a

y e a s t w h e n d e t e r m i n e d b y p e r c e n t g a i n i n w e i g h t of r a i n b o w t r o u t .
A lso

statistical analysis

(control) and D iets
6.

s h o w e d D i e t 2 t o b e s u p e r i o r to D i e t 8

1, 3, 4, a n d 6 to b e e q u a l to D i e t 8.

F e e d i n g t h e d r y d i e t s d e s c r i b e d i n t h i s p a p e r to r a i n b o w

a n d b r o o k t r o u t d i d n o t c a u s e a r e d u c t i o n i n n u m b e r s of r e d b l o o d
cells p e r

m i l l i m e t e r of b lo o d a s

w as o r ig in a lly thought.

w e r e a s high an d h ig h e r th a n th o se f r o m
fe d a n a ll- b e e f li v e r diet.
and in h a tc h e r ie s

A t no t i m e

Counts

rainbow and brook trout

during th e se e x p e rim e n ts

w h e re the d ie ts w e re fed on a p ro d u c tio n s c a le

w as nutritional anem ia

evident.

F e e d in g D iet 1 and D iet 2 fo r

107
tw elve m o n th s

to r a i n b o w a n d b r o o k t r o u t w i t h o u t r a w m e a t s u p p l e ­

m e n t a t i o n d i d n o t c a u s e a r e d u c t i o n i n n u m b e r s of r e d b l o o d c e l l s .
7.

F e e d i n g a r a w m e a t s u p p le m e n t c a n be d i s p e n s e d with,

o n a p r o d u c t i o n s c a l e , f o r a s long as th r e e w eek s

w ithout a d v e r s e l y

affecting tro u t g ro w th ra te .
8.
in the

com binations

to r e a r

suitable,

sh o w n a n d w ith a w eek ly m e a t su p p le m e n ta tio n ,

ra in b o w an d b ro o k tro u t on a p ro d u ctio n scale.
9.

are

A l l of t h e d i e t i n g r e d i e n t s l i s t e d i n T a b l e 4 a r e

The d ry p e lle te d ra tio n s u se d during these

s u p e r i o r to r a w

m e a t d ie ts in enough r e s p e c t s

ad o p tio n fo r f u ll- s c a le h a tc h e ry feeding.
a d o p t io n of d r y p e l l e t e d d ie ts
e rie s in M ichigan a s

experim ents

to w a r r a n t t h e i r

A d i r e c t r e s u l t of t h e

1 a n d 2 b y a l l the

state fis h h a tc h ­

s t a n d a r d d i e t s i n c r e a s e d t r o u t p r o d u c t i o n (in

p o u n d s ) b y 60 p e r c e n t a n d r e d u c e d f i s h f o o d e x p e n d i t u r e b y 40 p e r ­
cent.
10.
m ajor

A s d e m o n s t r a t e d by one e x p e r i m e n t , a n tib io tic s m a y play a

r o le in b a c t e r i a l d is e a s e p re v e n tio n in tr o u t w hen fed a s a

c o n s t i t u e n t of d r y p e l l e t e d r a t i o n s .
11.

Suggestions fo r fu tu re

stu d ies a r e indicated.

BIBLIO G RAPH Y

A g e r s b o r g , H. P . K .
1934.

A n in ex p en siv e b alan ced diet fo r tro u t and salm on.
A m . F i s h . S o c . 6jl, 1 5 5 - 1 6 2 .

B rockw ay,
1953.

Trans.

D onald R.
F is h food p e lle ts
pp. 92-93.

show p ro m ise .

Prog.

F i s h Cult.

15 (2),

C h u r c h i l l , W . S.
1944.

T h e f o o d of t r o u t .
3-6.

W i s c o n s i n C o n s e r v . B u l l . 9, N o . 5,

D a v i s , H . S.
1935.

C h eap e r tro u t foods.

P r o g . F i s h C u l t . N o . 9, 7 - 1 0 .

D a v i s , H. S . , a n d L o r d , R . F .
1 9 ^ 9 . T h e u s e of s u b s t i t u t e s f o r
T r a n s . A m . F i s h S o c . 59,

f r e s h m e at in
160-167.

the d iet

of t r o u t ,

D u e l , C h a r l e s R . , H a s k e l l , D a v i d C . , a n d T u n i s o n , A . V.
1942.
T h e N ew Y ork State F i s h H a tc h e ry feed ing C h a rt.
F ish ­
e r i e s R e s e a r c h B u l l . N o . 3, N . Y . C o n s e r . D e p t . , A l b a n y ,
N.Y .
D o n a ld s o n , L . R,
1935.
T h e u s e of s a l m o n b y - p r o d u c t s a s f o o d f o r young king
salm on.
T r a n s . A m . F i s h . S o c . 65^, 1 6 5 - 1 7 1 .
E i n a r s e n , A. S ., a n d R o y a l , L .
1929.
W hat sh a ll we fe ed?

Trans.

A m . F i s h . S o c . 59, 2 6 8 - 2 7 1 .

F o s t e r , F . J . , P e l n a r , J . , a n d H a g e n , W.
1939.
P r e l i m i n a r y r e s u l t s of a n e x p e r i m e n t o n t h e i n c l u s i o n of
a p p le f l o u r in f o o d s f e d to young s a lm o n o id s .
P rog. F ish
C u lt. N o. 47, 4 9 -5 1 .

108

109
G utsell,

J.

1939.

S.
F in g e r lin g tr o u t feeding e x p e rim e n ts, Leetow n,
P r o g . F i s h C u lt. No. 45, 3 2 -4 1 .

1938.

H a e m p e l, O.
1927.

T h e s i g n i f i c a n c e of v i t a m i n s i n t h e f o o d of d o m e s t i c a n i ­
m a ls , esp ecially fish.
A l l g . F i s c h e r e i - Z e i t g . 2, 2 0 - 2 3 ;
B i o l . A b . 4, N o . 2 , 41 3 5 ( 1 9 30 ) .

H a g e n , W.
1940.

S u itin g th e d i e t to the h a t c h e r y .
11-15.

P r o g . F i s h C u l t . N o . 51,

H e a r d , R . D. H .
1930.

I n v e s t i g a t i o n s o n t h e n u t r i t i o n of s p e c k l e d t r o u t .
A m . F i s h . Soc. 60, 1 4 0 -1 4 5 .

H e w i t t , E . W.
1937.
Som e r e c e n t w ork on fatty liv e rs
C u lt. N o . 27, 1 1 -15.

in tro u t.

Trans.

P rog. Fish

Ide, F . P .
1942.
A v a i l a b i l i t y of a q u a t i c i n s e c t s a s f o o d of t h e s p e c k l e d
t r o u t , S a lv e lin u s f o n t i n a l i s , T r a n s . N o rth A m e r . W ildlife
C o n f . 7, 4 4 2 - 4 5 0 .
Id y ll, C.
1942.

F o o d o f r a i n b o w , c u t t h r o a t a n d b r o w n t r o u t i n th e C o w i c h a n
R iv e r s y s te m , B r it is h C olum bia.
J. F is h . R e s. Bd. Can.
5, N o .

M e C a y , C. M .
1934.
G row th.

5, 4 4 8 - 4 5 8 .

Prog.

F i s h . C u l t . N o . 1, 2 - 7 .

M c C a y , C . M.
1 9 3 7 a . O b s e r v a t i o n s o n t h e n u t r i t i o n of t r o u t .
The p r o g r e s s iv e
F i s h C u l t u s t , U . S . B u r e a u of F i s h e r i e s , M e m o . 1 - 1 3 1 ,
N o. 30, p p .

1-24.

M c C a y , C. M.
1 9 3 7 b . T h e b i o c h e m i s t r y of f i s h .
V o l. VI, p p . 4 4 5 - 4 6 8 .

A n n u a l R e v i e w of B i o c h e m i s t r y ,

110
M cCay,
1939.

M cCay,
1927.

M cCay,
1940.

C . M.
The vitam ins.
(A s y m p o s i u m ) ,
c a n M e d ic a l A s s o c ., C hicago.

pp. 599 -6 0 0,

The A m e r i ­

C . M . , a n d D i l l e y , W. E .
F a c t o r H i n th e n u t r i t i o n of t r o u t .
Soc. 57, 250-260.

T rans. Am. F ish.

C . M . , a n d P h i l l i p s , A . M.
F e e d s f o r the f is h h a t c h e r ie s .
18-21.

P r o g . F i s h C u l t . No. 52,

M c C a y , C . M . , a n d T u n i s o n , A. V.
1 9 3 5 . R e p o r t of e x p e r i m e n t a l w o r k a t t h e C o r t l a n d ( N .Y .) e x ­
p e r i m e n t a l h a t c h e r y f o r t h e y e a r 1 93 4 .
P r o g . F i s h Cutl.
N o . 7, 8 - 9 .
M c C a y , C . M . , T u n i s o n , A . V . , C r o w e l l , M . , a n d P a u l , H.
1 9 3 6 . T h e c a l c i u m a n d p h o s p h o r o u s c o n t e n t of t h e b o d y of t h e
b r o o k t r o u t i n r e l a t i o n to a g e , g r o w th , a n d food.
J.
B i o l . C h e m . 1 1 4 , N o . 1, 2 5 9 - 2 6 3 .
M c C a y , C. M ., T u n i s o n , A. V ., C r o w e l l , M ., T r e s s l e r , D. K .,
M c D o n a l d , S. P . , T i t c o m b , J . W . f a n d C o b b , E . W.
1931.
T h e n u t r i t i o n a l r e q u i r e m e n t s of f r o n t a n d c h e m i c a l
c o m p o s i t i o n of t h e e n t i r e t r o u t b o d y .
T rans. Am, F ish.
Soc. 6 R 58-82.
M c C raw , B ru c e M.
1952. F u r u n c u l o s i s

of f i s h .

S pecial S cientific r e p o rt:

F ish eries

N o . 84.
M c L a r e n , B . A . , H e r m a n , E . F . , a n d E l v e h j e m , C. A.
1947.
N u t r i t i o n of t r o u t , s t u d i e s w i t h p r a c t i c a l d i e t s .
S o c . E x p t l . B i o l . M e d . 6jj, 9 7 - 1 0 1 .

Proc.

M c L a r e n , B a r b a r a A ., K e l l e r , E l i t h a b e t h , O 'D o n n e l l, D. Jo h n , a n d
E l v e h j e m , C. A.
1947.
T h e n u t r i t i o n of r a i n b o w t r o u t .
I. S t u d i e s of v i t a m i n r e ­
quirem ents.
A r c h . B i o c h e m . 15, N o . 2 ( 1 6 9 - 1 7 8 ,

Ill
P h i l l i p s , A . M . , B r o c k w a y , D. R . , R o d g e r s , E . O . , R o b e r t s o n , R. L . ,
G o o d e l l , H e r b e r t , T h o m p s o n , J. A ., a n d W illo u g h b y , H a r v e y .
1947.

T h e n u t r i t i o n of t r o u t .
F i s h . R e s . B u l l . , No.
H a t c h e r y R e p t . , N o . 16 , 35 p p .

P h i l l i p s , A. M .,
M c C a y , C . M.
1940.

Raney, E.
1941.

T u n i s o n , A. V . , F e n n , A. H . , M i t c h e l l ,

C. R . , a n d

T h e n u t r i t i o n of t r o u t .
C o r t l a n d H a t c h e r y R e p t . N o . 9,
30 p p . , N .Y . S ta te C o n s e r v a t i o n D e p t., A lb a n y , N.Y,
C . , a n d L a c h n e r , E . A.
A u t u m n f o o d of r e c e n t l y p l a n t e d y o u n g b r o w n t r o u t i n
s m a l l s t r e a m s of c e n t r a l N e w Y o r k .
T ran s. Am. F ish.
S e c . 74, 1 0 6 - 1 1 1 .

S e k in e , H ., a n d K a k iz a k i,
1931.

10, C o r t l a n d

Y.

B i o c h e m i c a l s t u d i e s o n s a l m o n i d a e , VII. J . A g r . C h e m .
S o c . J a p a n 7, 3 6 - 4 0 ; C . A . 25 , No. 13, 3401 ( 1 9 31 ).

S n e d e c o r , G e o r g e W.
S ta tis tic a l M ethods.
A m e s , Iowa.

4th e d itio n .

Iowa State C ollege P r e s s ,

S t i l e s , E . W . , a n d R u s s , H. C .
1938.
M e a t diet su p p le m e n ts , and th e ir effect on grow th and
h e a l t h of f i n g e r l i n g t r o u t .
P r o g . F i s h . C u l t . N o . 37,
10- 16.

T h o m p s o n , W. T .
1929.
A r i v a l to l i v e r .
T itcom b,
C. M.
1928.

T r a n s . A m . F i s h S o c . 59_, 1 6 8 - 1 7 3 .

Jo h n W ., C obb, E b en W ., C ro w ell, M a ry F ., and M cC ay,
T h e n u t r i t i o n a l r e q u i r e m e n t s a n d g r o w t h r a t e s of b r o o k
trout.
T r a n s . A m . F i s h S o c . V o l. 5 8 , p p . 2 0 5 - 2 3 1 .

T i t c o m b , J . W . , C o b b , E . W . , C r o w e l l , M. a n d M c C a y , C. M.
1929.
T h e r e l a t i v e v a l u e of p l a n t a n d a n i m a l b y - p r o d u c t s a s
f e e d s f o r b r o o k tr o u t an d the b a s ic n u tritio n a l re q u ir e m e n ts
o f b r o o k t r o u t i n t e r m s of p r o t e i n s , c a r b o h y d r a t e s , v i t a m i n s ,
inorganic elem en ts and roughage.
T r a n s . A m . F i s h . S oc.
59,

126-145.

1 12
T u n i s o n , A . V . , B r o c k w a y , D. R . , M a x w e l l J .
M c C a y , C. M.
1942.

M . , D o r r , A. L . , a n d

T h e n u t r i t i o n of t r o u t .
F i s h . R e s . B u l l . N o . 4, N . Y . S ta t e
C o n s e r v . D e p t., B u r . F i s h C u ltu re , A lbany, N .Y ., C o rtlan d
H a t c h e r y R e p t , N o . 11, 45 p p .

T u n i s o n , A. V ., B r o c k w a y , D. R . ,
M cK ay , C. M ., P a l m , C. E ., a n d
1 9 4 3 . T h e n u t r i t i o n of t r o u t .
N ew Y ork C o n se rv atio n

S c h o f f e r , H. B . , M a x w e l l , C. M . ,
W e b s t e r , D. A.
C o r t l a n d H a t c h e r y R e p o r t N o . 12.
D e p a r tm e n t, A lbany, N ew York.

T u n i s o n , A . V . , a n d M c C a y , C. M .
1 9 3 3 . T h e n u t r i t i o n a l r e q u i r e m e n t s of b r o o k t r o u t .
F i s h . A m . F i s h S o c . 63 , 1 6 7 - 1 7 7 .
T u n i s o n , A. V ., a n d M c C a y , C. M.
1 9 3 5 a . T h e n u t r i t i o n a l r e q u i r e m e n t s of t r o u t .
N o . 1 1 , 17.
T u n i s o n , A . V , , a n d M c C a y , C . M.
1 9 3 5 b . T h e n u t r i t i o n a l r e q u i r e m e n t s of t r o u t ,
Soc.

T rans, Am.

P r o g . F i s h Cult.

T rans. Am. F ish.

65^, 3 5 9 - 3 7 5 .

T u n i s o n , A. V . , a n d P h i l l i p s .
1 9 3 9 . T h e n u t r i t i o n of T r o u t .
C o r tl a n d H a tc h e r y R e p o r t No. 8
f o r the y e a r 1939, N ew Y o r k State C o n s e r v a ti o n D e p a r tm e n t,
A l b a n y , N .Y .
T u n i s o n , A . V . , P h i l l i p s , A . M . , S h a f f e r , H. B . , M a x w e l l , J . M . ,
B r o c k w a y , D . R . , a n d M c C a y , C . M.
1 9 4 4 . T h e n u t r i t i o n of t r o u t .
F i s h R e s . B u l l . N o. 6, N .Y . S t a t e
C o n s e r v . D e p t . , A l b a n y , N . Y . , C o r t l a n d H a t c h e r y R e p t . No.
13, 20 p p .
W a le s , J. H ., an d M o o r e , M y ro n .
1 9 3 8 . P r o g r e s s R e p o r t of T r o u t F e e d i n g E x p e r i m e n t s ,
C a l i f o r n i a F i s h a n d G a m e , 24, 126.
W e l l e s , G . D.
1944. T r o u t a n d th e i r fa v o r ite food.
49, No.

7, 7 8 - 7 9 ,

84-85.

193 7.

G am e B re e d e r and S portsm an

113
W ilk in so n , J. T.
1938.
N o t e s o n t h e u s e of s u p p l e m e n t s f o r f r e s h m e a t i n t h e
p r o p a g a t i o n of b r o o k , r a i n b o w , a n d b r o w n t r o u t i n
M ichigan.
T r a n s . A m . F i s h . S o c . 68 , 9 6 - 1 1 7 .
W illoughby, H arv e y .
1953.
Use of p e l l e t s a s t r o u t fo o d .
P r o g . F i s h C u l t . 15 (3): 1 2 7 - 1 2 8 .
W olf, H a r o ld .
1953.
C olored F is h -F o o d P ellets.
P r o g . F i s h C u l t . 15 (4): 18 2.
W olf, L .
1945.

E.
D i e t a r y g i l l d i s e a s e of t r o u t .
F i s h . R e s . B u l l . No. 7,
N .Y . State C o n s e r v . D e p t., B u r e a u F i s h C u ltu re , A lbany,
N . Y . , 32 p p .