" ,' 2. 1.3% Nucw‘w- ......... REQUIREMENTS OF DEVELOPING SWINE. ; .‘_.f.§ Thesis Tor-‘the‘Deg’ree‘ ,ofiPh.; D ; f MICHIGAN STATE UNNERSITY': 5 -_i é if-‘liiig‘ f, ' ’- ‘ ~ * * ’ DENNIS owENMPIRAP' ’ 1.96:9"; ' ‘ intbi: .I'IIF- '—— u l i, (B R ."l R '1 This is to certify that the thesis entitled THE INFLUENCE OF SEX ON THE MINERAL REQUIREMENTS OF DEVELOPING SWINE presented by Dennis Owen Liptrap has been accepted towards fulfillment of the requirements for PhD degree in Animal Husbandry awe/m) Major professor Date 5/8/69 0-169 Mimigan Shite University at?” t .3 use; ABSTRACT THE INFLUENCE OF SEX ON MINERAL REQUIREMENTS OF DEVELOPING SWINE by Dennis Owen Liptrap Five experiments involving 97 boars, 97 gilts and 61 barrows were conducted to examine the influence of sex on mineral requirements of developing swine. Experiments 1 and 2 examined the calcium requirement of developing boars and gilts, and experiments 3, 4 and 5 studied the zinc requirement of developing boars, barrows and gilts. Twelve boars and 12 gilts in experiment 1 and 24 boars and 24 gilts in experiment 2 were randomly allotted in a factorial design to 0.6, 0.9 or 1.2% dietary calcium. Phosphorus was maintained at 0.5% of the diet in both ex- periments. The pigs were fed and watered ad libitum and blood samples were obtained in experiment 1 by vena cava punow ture initially. at 4, 8 and 12 weeks, and upon completion of the experiment. All animals were slaughtered upon termination of the experiments, and carcass data were obtained in exp'eriw ment 1. The femur in experiment 1 and the fourth metacarpal. first lateral phalanx and turbinates in both experiments were saved for subsequent analysis. Boars gained faster and were slightly more efficient than gilts but feed consumption was not different. Increased dietary calcium caused a reduction D. O. Liptrap in growth rate and gain/feed ratio of both boars and gilts. Furthermore, increased dietary calcium tended to increase serum calcium. serum alkaline phosphatase activity and bone calcium and to decrease bone breaking strength and serum inorganic phosphorus. Gilts had slightly higher bone ash concentration and stronger bony matrices than boars. Dietary calcium level did not influence the degree of turbinate atrophy; however, cartilage was conspicuously present whenever turbinate atrOphy was evident. Inflammation was not a causative factor in the turbinate atrophy observed in these experiments. Sixty-one boars, 61 gilts and 61 barrows were allotted in three experiments (Exp. 3. 4 & 5) to dietary zinc levels from 22 to 90 ppm. Dietary calcium was maintained at 0.7% in all experiments. Feed and water were supplied §g_libitum and blood samples were obtained on 4 occasions (initially, 4 and 8 weeks, and upon termination of the experiment). Growth rate, daily feed intake, serum zinc concentration and serum alkaline phosphatase activity were significantly reduced by inadequate dietary zinc; however. gain/feed ratio was not appreciably altered by low dietary zinc levels. In experiments 3 and 4, zinc deficiency symptoms, including re- duced growth, feed intake and serum alkaline phOSphatase activity along with parakeratosis. were more severe in boars and gilts than barrows. Parakeratosis was not observed in the barrows fed the low zinc diets, and serum zinc concentrations were similar for all sexes on equivalent dietary zinc levels. D. O. Liptrap In experiment 5. growth rate and feed intake were more severely depressed by inadequate zinc in barrows and gilts than boars; however. serum alkaline phosphatase activity was lower in boars and gilts than barrows. Serum zinc concentration of the boars was slightly lower than that of the barrows and gilts on the low zinc diet. In experiment 5, parakeratosis was ob- served in all sexes, and the incidence was greatest in the barrows. Combining the results from experiments 3. 4 and 5, 26.1% of the boars and gilts fed diets containing less than 30 ppm of zinc developed parakeratosis while only 13% of the barrows developed parakeratosis. THE INFLUENCE OF SEX ON THE MINERAL REQUIREMENTS OF DEVELOPING SWINE BY Dennis Owen Liptrap A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Animal Husbandry 1969 Dennis Owen Liptrap Candidate for the degree of Doctor of Philosophy DISSERTATION: The Influence of Sex on the Mineral Requirements of Developing Swine. OUTLINE OF STUDIES: Main Area: Animal Husbandry (Nutrition) Minor Areas: Biochemistry and Physiology BIOGRAPHICAL ITEMS: Born: September 14, 1943, Williamsport, Indiana Undergraduate Studies: Purdue University, 1961-1962 University of Kentucky, 1962-1965 Graduate Studies: Michigan State University, 1965-1969 EXperience: Graduate Assistant, 1965~1969 MEMBER: American Society of Animal Science Society of Sigma Xi Gamma Sigma Delta Alpha Zeta ii ACKNOWLEDGEMENTS The author wishes to express his sincere appreciation to Drs. E. R. Miller and D. E. Ullrey for their expert guidance and counsel throughout his graduate program and for their critical reading of this manuscript. Appreciation is also extended to Drs. R. W. Luecke. E. P, Reineke and especially J. A. Hoefer for their helpful guidance and interest during this writer's graduate program. The association with these scientists will always be cherished and will provide con- tinued inspiration. Sincere gratitude is expressed to Dr. R. H. Nelson and the Animal Husbandry Department for the use of facilities and animals and for financial support in the form of a graduate assistantship. Thanks are extended to Mr. D. C. Brown, Manager, and the swine farm staff for their interest in this work and cooperation in caring for the experimental animals. A Special note of thanks goes to the fellow graduate students and laboratory staff for their assistance and encouragement and to Mrs. Kathryn Ide for her skillful typing of this thesis. Above all. the author is indebted to his wife, Virginia, whose love and encouragement have made this study worthwhile. 111 I. II. III. TABLE OF CONTENTS Page Introduction 1 Review of Literature 3 A. Factors influencing the calcium requirement of swine. 3 B. The biological role of zinc and factors affect- ing zinc requirement of animals. 11 1. Biological role of zinc. 11 2. Zinc deficiency. 17 a. Swine 17 b. Other species 19 3. Factors influencing zinc requirement. 23 a. Dietary factors 23 b. Other factors 30 c. Toxicity of zinc 32 C. Sex differences and nutrient interactions. 33 Experimental Procedure 40 A. Introduction 40 B. The experiments. 43 1. Experiment 1 43 2. Experiment 2 43 3. Experiment 3 44 4. Experiment 4 an 5. Experiment 5 45 C. Chemical analytical procedures 45 1. Blood 45 iv Table of Contents (Cont.) D. 2. Bone 3. Ham 4. Feed Statistical analysis IV. Results and Discussion A. Influence of sex on the calcium requirement of deveIOping swine. 1. Experiment 1. 2. Experiment 2. Influence of sex on the zinc requirement of developing swine. 1. Experiment 3. 2. Experiment 4. 3. Experiment 5. 4. Correlation Coefficients. V. Summary A. B. C. D. E. Experiment 1. Experiment 2. Experiment 3. Experiment 4. Experiment 5. VI. Conclusions VII. Bibliography VIII. Appendix 51 51 61 67 67 73 77 82 85 85 86 86 87 88 89 91 111 Figure :—w_~.e '?~1:-_xx.:n ~ ~- a ‘U‘ LIST OF FIGURES Loadwdeflection curves of femurs from boars and gilts fed 0.6, 0.9 or 1.2% dietary calcium (Exp. 1). Photomicrographs of normal and atrophied turbinates: dorsal scroll. normal (A) and abnormal (B); lateral attachment. normal (C) and abnormal (D); ventral scroll. normal (E) and abnormal (F). Load-deflection curves of metacarpals from boars and gilts fed 0.6. 0.9 or 1.2% dietary calcium (Exp. 2). Boars fed a diet containing less than 30 ppm of zinc (Exp. 3). Barrows fed a diet containing less than 30 ppm of zinc (Exp. 3). Gilts fed a diet containing less than 30 ppm of zinc (Exp. 3). vi 57 59 65 71 71 71 Table ‘Q 10 ll 13 14 LIST OF TABLES Composition of the diets (Experiments 1 & 2) Composition of the basal diet (Experiments 3. 4 and 5). Chemical analyses of eXperimental diets. Summary of pig performance and carcass and ham measurements from experiment 1. Summary of serum mineral concentrations and enzyme activity from experiment 1. Summary of metacarpal. femur. and turbinate measurements in experiment 1. Correlation coefficients between and within bone,blood and performance parameters (EXperiment 1). Summary of pig performance in experiment 2. Summary of bone composition. density. strength and histolOgy in experiment 2. Correlation coefficients between and within bone and performance parameters (Experiment 2). Summary of pig performance and blood analysis in experiment 3. Summary of pig performance and blood analysis from experiment 4. Summary of pig performance and blood analysis from experiment 5. Correlation coefficients between and within blood and performance parameters (Experiments 3, 4 and 5). vii 1:2 52 54 56 60 62 63 68 7O 74 79 83 10 11 LIST OF APPENDIX TABLES Calendar periods when the experiments were conducted. Pig performance of boars and gilts fed three levels of calcium (Exp. 1). Carcass and ham data from boars and gilts fed three levels of calcium(Exp. 1). Femur size, strength and density from boars and gilts fed three levels of calcium (Exp. 1). Metacarpal composition and turbinate histology from boars and gilts fed three levels of calcium (Exp. 1). Serum calcium and phosphorus concentrations in boars and gilts fed three levels of calcium (Exp. 1). Serum zinc and alkaline phosphatase from boars and gilts fed three levels of calcium (Exp. 1). Pig performance and turbinate histology of boars and gilts fed 0.6% dietary calcium (Exp. 2). Pig performance and turbinate histology of boars and gilts fed 0.9% dietary calcium (Exp. 2). Pig performance and turbinate histology of boars and gilts fed 1.2% dietary calcium (Exp. 2). Bone strength. density, size and composition from boars and gilts fed 0.6% dietary calm cium (Exp. 2). Bone strength. density. size and composition from boars and gilts fed 0.9% dietary cal— cium (Exp. 2). Bone strength. density, size and composition from boars and gilts fed 1.2% dietary cal~ cium (Exp. 2). viii 112 113 114 115 116 117 118 119 120 121 123 List of Appendix Tables (Cont.) 1.212 Page 14 Pig performance and blood data from boars, barrows and gilts fed 0 ppm additional zinc (Exp. 3). 124 15 Pig performance and blood data from boars, barrows and gilts fed 30 ppm additional zinc (Exp. 3). 125 16 Pig performance and blood data from boars. barrows and gilts fed 60 ppm additional zinc (EXP. 3). 126 17 Pig performance and blood data from boars. barrows and gilts fed 0 ppm additional zinc (Exp. 4). 127 18 Pig performance and blood data from boars. barrows and gilts fed 20 ppm additional zinc (EXPo 4). 128 19 Pig performance and blood data from boars, barrows and gilts fed 40 ppm additional zinc (Exp. 4). 129 20 Pig performance and blood data from boars. barrows and gilts fed 0 ppm additional zinc (Exp. 5). 130 21 Pig performance and blood data from boars. barrows and gilts fed 40 ppm additional zinc (Exp. 5). 131 ix I. INTRODUCTION The National Research Council has published generally accepted nutrient requirements for swine that have been determined by extensive research: however. new management conditions. more muscular animals. and expanded nutritional knowledge prompt continual reevaluation of these published requirement levels. Sex differences in growth rate. feed consumption. feed utilization. body composition and several biochemical parameters are well described in the literature, and these differences suggest dissimilar metabolic rates between the sexes. Higher metabolic rates have been reported for men than women, but the differences disappeared when metabolic rate was expressed on a per unit body-weight basis (Kleiber. i961). Boars grow faster, consume less feed and have more bone and lean tissue than gilts or barrows which should cause bears to require higher dietary nutrient concentrations than barrows or gilts when metabolic rates are equivalent. In fact. sex x nutrient interactions have been described for protein. energy and some minerals. Most previous studies on nutrient requirements of swine have been conducted with mixed lots of barrows and gilts and have not included boars. Thus, relatively little effort has been expended to delineate sex differences in swine. and the assumption has generally been made that sex does not substan- tially influence nutrient requirements. This study was undertaken to study the influence of sex on the mineral requirements of developing swine and to deter- mine if a sex x dietary mineral requirement interaction does exist. Serum mineral concentrations. serum enzyme activity. and bone strength and composition in addition to pig perform- ance were the criteria used in this study. A. II. REVIEW OF LITERATURE Factors Influencing Calcium Requirements of Swine. The calcium requirement of swine has been extensively studied by many workers but everyone does not agree on the optimum dietary level or the criteria used to evaluate this requirement. The National Research Council has published a requirement for the baby pig of 0.8% calcium and 0.6% phosphorus which agrees with the requirements published by Rutledge gt 3;. (1961). Miller g£_§l. (1962) and Zimmerman g: 31. (1963). These workers used mineral content and strength of the bone as important measures of dietary calcium adequacy in addition to the standard criteria of growth. feed efficiency and serum mineral concentrations. Zimmerman 23 31. (1960) reported maximum calcium retention in baby pigs when the diet contained 0.88% calcium and either 0.52 or 0.70% phOSphorus and thought this to be near the calcium requirement even though the ash and calcium content of bone increased with further increases in dietary calcium. Dietary calzium and phOSpnorus levels of 0.7% each were reported by kenahan 33 al. (1963) to be optimum for all criteria examined including growth, feed efficiency. bone ash and calcium content and serum calcium; however. Blair and Benzie (1964) concluded that at least 1.3% dietary calcium was needed for normal bone mineralization. The calm cium requirement seems to be much less for maximal growth than for Optimum bone mineralization. Combs and Wallace (1962) used rate and efficiency of gain to arrive at a requirement of 0.0% calcium for the 8 week old pig when the diet contained 0.4U% phosphorus. Washam 33 al. (1968) observed normal feed efficiency and serum calcium and phosphorus concentrations on a diet con- taining 0.37% calcium and 0.28% phosphorus, but 0.95% calcium and 0.73% phosphorus was needed to support maximum growth and skeletal mineralization. The calcium requirement of the grow- ing and finishing pig has not been studied as extensively as the requirement of the baby pig. Peo and Hudman (1963) recommended 0.6% calcium in the diet and a 1:1 calcium to available phOSphorus ratio. They observed growth depressions when dietary calcium levels exceeded 0.6%. Chapman gt al. (1963) reported calcium and phosphorus requirements of 0.8 and and 0.6% for the growing pig (weaning to 100 lbs.) and 0.7 and 0.5% for the finishing pig (100 lbs. to market). Their data also showed a higher requirement for optimal bone minw eralization than for liveweight gain. Libal 33 21° (1969) re- ported little difference in growth rate in going from 0.4 to 0.9% dietary calcium but found maximum bone strength on 0.65% calcium and either 0.65 or 0.90% dietary phosphorus. The calcium and phosphorus requirements published by the National Research Council are 0.65% and 0.5% for the growing pig and 0.5% and 0.4% for the finishing pig. A current interest in dietary calcium and phosphorus levels for growing pigs has been genera ated by the recently published work of Brown 33 al. (1966) and Pond gt al. (1966b) who reported that subOptimal dietary levels of calcium and/or abnormally high dietary levels of phOSphorus caused a pathological condition known as atrOphic rhinitis. They reported that atrophic rhinitis was characterized by a generalized nonninfectious osteitis fibrosa of the turbinate scrolls which could be produced by feeding diets containing N.R.C. levels of calcium and/or high phosphorus. Atrophic rhinitis could be prevented by feeding diets containing 1.2% calcium and 1% phosphorus. Other workers have not been able to duplicate these results but have shown the turbinate to be a very metabolically active tissue. Harmon gt £l° (1967, 1968) did not find any relationship between dietary mineral level and incidence of turbinate atrophy. They also reported that the ash and calcium content of the turbinates was less than that of the ribs and femur but the phosphorus content was similar for these tissues. Thus, the turbinates had a lower CazP ratio than the ribs and femur. Krusemark 33 31. (1968) 1;, found a more rapid 5Ca uptake by the turbinates as compared to the ribs or the femur and the turbinates were more sensitive to low dietary calcium than the other bones. Perhaps the nutrient most closely related to calcium metabolism and requirement is phosphorus. Utilization of dietary calcium is limited by the adequacy of dietary phos- phorus. Forbes (1965) reported an improved calcium balance in the rat when dietary phOSphorus was increased from 0.19% to 0.5% of the diet. Urinary excretion of calcium was greater on the low levels of phosphorus. Harmon gt §l° (1964) and Miller _et al. (1964b) both observed decreases in serum calcium con- contration as dietary phosphorus was increased. These reports would tend to indicate that the effect of phOSphorus on calcium metabolism occurs after absorption and level of phosphorus per as does not greatly affect calcium absorption from the gut. When dietary phosphorus is marginal to inadequate, the calcium to phosphorus ratio is probably more closely related to optimum calcium utilization than dietary phosphorus level itself. Many workers have reported studies where dietary calcium varied from 0.3% to 1.9% and dietary phosphorus from 0.2% to 1.95% of the diet and the calcium to phosphorus ratio varied from 0.2 to 3. These workers, who are too numerous to list here, generally agreed that when dietary phosphorus was 0.4% or less and CazP exceeded 1.8, a reduced growth rate would occur. Most of these workers concluded that a calcium to phosphorus ratio of 1.0 to 1.2 was most advantagecisztor growth. The effect of calcium to phosphorus ratios on feed efficiency is not as explicit as its effect on growth. Combs 32 al. (1966 and 1962a,b), and Hoefer gt al. (1960) all re- ported a decrease in feed efficiency when Ca:P exceeded 1.5 with only slight or no effect on intake. Lloyd 23 2l° (1961) and Zimmerman 33 El- (1963) did not find any difference in feed efficiency due to varying calcium to phosphorus ratios but did observe decreases in feed intake, while Peo and Hudman (1963) observed that 0.9% and 1.2% dietary calcium with 0.6% phos- phorus decreased gain and improved feed efficiency when compared to a diet containing 0.6% calcium and phosphorus. Vitamin D is another nutrient essential for normal calcium metabolism and is required for the active absorption of calcium from the gastrointestinal tract (Dowdle 23 31.. 1960), and it is especially important for calcium absorption from low cal- cium diets. Wasserman and Taylor (1966) reported that the administration of vitamin D3 to rachitic chicks induced forma- tion of a protein in the intestinal mucosa capable of binding calcium. Furthermore, an improvement in calcium absorption from the intestine was observed simultaneously with the appear- ance of the calcium binding protein. This protein was later 4 and to bind one shown to have a molecular weight of 2.8 x 10 atom of calcium per mole of protein (Wasserman gt_gl., 1968). Miller 32 al. (1964a) reported that supplemental vitamin D improved serum calcium and phosphorus concentrations and bone mineralization of baby pigs not exposed to sunlight. They later demonstrated that in the absence of vitamin D, excessive amounts of calcium, phosphorus and magnesium were excreted in the feces which indicated reduced absorption or increased in- testinal secretion (Miller 22 al., 1965c). Combs 22 al. (1966) also reported that supplemental vitamin D improved calcium di- gestibility in pigs. In addition to the influence of vitamin D on calcium balance, the previous calcium status of the animal affects calcium utilization. Hansard and Plumlee (1954) re- ported greater absorption and retention of dietary calcium and lower endogenous loss of calcium from rats fed low calcium diets. Benson £2.2l- (1969) agreed with the work of Hansard and Plumlee but stated that absolute retention favored the high calcium diets. Itoh gt 2;. (1967) reported that sows fed high calcium diets transferred more total calcium to their fetuses but the percent transfer was not different from the low calcium treatment. Other minerals, primarily magnesium, interact with and alter utilization of calcium. Hart and Steenbock (1913) first reported that the addition of magnesium to a bran diet for young pigs increased urinary excretion of calcium which may result in a negative calcium balance. Much later Miller gt al, (1965b) obtained this same result. In another paper, Miller §£_§l. (i965a) reported reduced serum calcium concen- trations and bone mineralization when either a deficiency or excess of magnesium existed. Rinehart 33 El- (1968) reported that potassium deficiency in the chick caused a decrease in “50a and 32P uptake by the bone and decreased bone ash. Thompson 33 al. (1959) and Berry 33 El! (1961) did not find any effect of dietary zinc on calcium metabolism. Lactose additions to diets have been shown by many workers to have a beneficial effect on calcium absorption. Ali and Evans (1966) reported that calcium was absorbed primarily from the ileum and lactose stimulated calcium absorption from this section of the small intestine. Ali and Evans (i967a,b), Evans and Ali (1967i Wasserman and Lengeman (1960) and Forbes (1961) all reported increased calcium absorption caused by lactose additions to the diet and postulated that the effect was due to a change in gut pH caused by the lactose. In addition, Wasserman and Comar (1959) and Vaughan and Filer (1960) demonstrated that several other sugars besides lactose stimulated calcium absorption. In spite of the large number of reports to the contrary, Menahan gt_§l. (1963) concluded that lactose had no beneficial effect on calcium absorption; however, their data appeared to show some benefit for lactose. The addition of EDTA to animal diets has not proven beneficial to calcium absorption or utilization (Ali and Evans, 1966, 1967a,b; Evans and Ali, 1967: Forbes, 1961; Harmon 22 al.. 1964). 10 Other factors, such as source of protein, dietary fat con- tent, age and sex, have-been shown to affect calcium require» ment. Forbes (1964) observed that the inclusion of soybean protein in the rat diet inhibited the utilization of dietary calcium. Miller 92 gl. (1965d) reported that pigs fed soy protein excreted excessive amounts of fecal calcium and other minerals. This effect of soy protein on calcium metabolism probably involves phytic acid which will complex with calcium (Maddaiah, 1964). Hendricks 22 El- (1969) observed that high dietary levels of soybean protein depressed bone mineralization which could not be overcome by additional vitamin D; however, elevated protein had no effect on serum calcium and only slight- ly decreased serum phosphorus. The addition of 10% tallow to swine diets was reported by Newman 23 El! (1964) to cause a 5% reduction in calcium digestibility; however, they could not duplicate this result in 1967. Tillman and Brethour (1958) could not demonstrate a consistent effect of corn oil on the apparent digestibility of dietary calcium. Age has been shown to have a negative relationship to calcium absorption and a positive relationship to calcium excretion (Benson gt $1., 1969; Hansard 33 al.. 1961). Whedon (1959) observed in humans that insufficient dietary calcium intake over a long period of time seemed to predispose osteoporosis and possibly older females may require higher calcium levels than males to main- 11 tain a positive calcium balance and prevent osteoporosis. McLean and Urist (1955) reported that the administration of estrogen caused increased formation of endosteal bone in the female rat and chick while testosterone and prOgesterone had no effect on endosteal bone formation. In the male rat, testosterone administration caused a lengthening of the long bones, but neither testosterone nor estrogen altered endosteal bone formation in the male (McLean and Urist, 1955). The Biological Role of Zinc and Factors Affecting Zinc Require- ment of Animals. 1. Biological role of zinc. As early as 1921, Bertrand and Vladesco reported a high concentration of zinc in the testes and semen of stallions. They also reported the presence of zinc in the reproductive organs of the bull, man and herring and postulated that the element Zinc might play an important role in reproduction.. Later Keilin and Mann (1940) found that the enzyme carbonic anhydrase from red blood cells contained 0.33% zinc as a part of its molecule. Mawson and Fischer (1952) examined the zinc content and carbonic anhydrase activity of rat and rabbit prostate and found a significant positive correlation between the zinc content and carbonic anhydrase activity of the rat 12 prostate with the highest zinc concentration and enzyme activity in the dorsolateral prostate. Furthermore, they concluded that all prostatic zinc was not bound in the carbonic anhydrase molecule, as the rabbit prostate was high in zinc but very low in carbonic anhydrase activity. Hove 33 al. (1940) reported that the in Eitrg_activity of the enzyme alkaline phosphatase from the intestine was increased 40 to 100% by the addition of zinc. They also found that zinc deficiency caused a decrease in the activity of this enzyme in the rat. In later studies with the pig, Luecke gt El! (1958) observed that zinc deficiency caused a reduction in the activity of serum alkaline phosphatase which could be overcome by dietary zinc supplementation, but zinc deficiency had no effect on lactic dehydrogenase activity. Vallee and Hoch (1956) had previously reported that alcohol dehydrogenase from horse liver was a zinc metalloenzyme. In 1967, Prasad reviewed the metabolic role of zinc and reported that zinc was known to be a constituent of the following en~ zymes in addition to those previously mentioned: pancreatic carboxypeptidase, tryptcphan desmolase, malic dehydrogenase, glutamio dehydrogenase, lactic dehydrogenase and probably other pyridine nucleotide-dependent metallodehydrogenases. In addition, zinc increased the activity of many other enzymes inm eluding arginase, enolase, yeast aldolase, oxalacetic decarboxym lase, lecithinase, histidine deaminase, carnosinase and several peptidases. 13 Montgomery g3 gl. (1943) and more lately Czerniak gg’gl. (1962) and Rubini g3 gl. (1961) have reported that the pancreas wasthe main source of fecal zinc. Pancreatic zinc is thought to be a part of the enzyme carboxypeptidase and may be inn volved in insulin and glucagon formation (Prasad, 1967). Pekas (1966) contradicted these reports and stated that zinc excretion in the pig was primarily a result of intestinal se- cretion and subsequent fecal excretion. A total fistula of the gall bladder, pancreas or 40 cm. segment of the small intestine did not dramatically reduce fecal excretion of zinc, demon- strating that these glands do not contribute a major portion of the excreted zinc. These results were unexpected because the pancreas of the dog had contributed a large proportion of the total excreted zinc, but the pancreatic zinc secretion of the pig was only 10% that of the dog (Pekas, 1966), Hiers gg gl. (1968) reported that large quantities of zinc were se- creted into the rumen, reticulum and small intestine of the calf; however, most of the secreted zinc was reabsorbed in the abomasum and lower small intestine. Since the early report of Bertrand and Vladesco, the zinc concentrations in the reproductive tract have been extensively studied. Many workers have shown that the uptake of zinc by the male reproductive organs is influenced by various hormones. Gunn g2 gl. (1960a) reported that administration of 0.2 mg. per 14 day of interstitial cell-stimulating hormone (ICSH) to hypo- physectomized rats caused a 7-fold increase in 65Zn uptake by the dorsolateral prostate and a 19-fold increase in 652n uptake by the total prostate of control animals. Furthermore, they concluded that 65Zn uptake by the dorsolateral prostate of the hypophysectomized rat was a sensitive assay for ICSH activity. In another paper these same workers. Gunn gt_g;. (1960b) reported that doses of ICSH which maintained 65Zn uptake by the testes of hypophysectomized rats at control levels only maintained 65Zn uptake by the dorsolateral prostate at 20% of control values. Later, in 1961, Gunn 23 El! further reported that follicle stimulating hormone (FSH) was much less effective in preventing the decrease in zinc uptake by the prostate after hypophysectomy, and growth hormone and prolactin had no bene- ficial effect on zinc uptake. Millar gg,gl, (1960) found that gonadotrophin and testosterone injections stimulated growth in the sex organs of the zinc deficient male rat; however, the zinc concentration of the enlarged dorsolateral prostate was not different from the non-injected, zinc-deficient controls. They showed that testicular atrophy of the zinc-deficient, immature rat could be reversed by gonadotrophin injection, but once the testis had matured and produced sperm, tubular atrophy could not be reversed. They concluded that testicular atrophy in zinc deficiency is probably due to an inadequate zinc 15 supply to the testis and that the availability of sufficient zinc for incorporation at high concentration into spermatozoa was essential for the survival of the germinal epithelium and maintenance of Spermatogenesis. In two papers, Rudzik and Riedel (1960a.b) studied the effects of adrenalectomy and ACTH treatment on zinc metabolism of the male rat. Adrenalec- tomy caused a reduction in the zinc concentration of the pros- tate and blood and a decrease in the uptake of 65Zn by the testis and dorsolateral prostate. Daily treatment with cortisone resulted in normal zinc concentration and uptake values. Adrenal corticotrophic hormone (ACTH) injections to hypophysectomized rats partially prevented the decrease in 65211 uptake by the prostate due to hypophysectomy. Serum zinc levels were decreased by ACTH treatment in both intact and hypophysectomized animals which would suggest increased mobility and redistribution of the zinc. They also suggested a possible relationship between zinc and adrenal corticosteroid formation. The involvement of zinc in the female reproductive tract is not well documented; however, several recent papers have reported alkaline phosphatase, a zinc metalloenzyme, activity in the ovary and endometrial tissue of swine. Goode gg_gl. (1965) and Akins g£.gl. (1969) both reported activities as high as 950 units per gram in endometrial and luteal tissues 16 of gilts, and the enzyme activity varied with the estrus cycle of the gilt. Since there is some evidence that alkaline phosphatase activity in the endometrium is under hormonal con- trol, the uptake of zinc by the endometrium during the estrus cycle would be of interest to see if it would parallel the cyclic changes in enzyme activity. O'Bannon (1966) reported high alkaline phosphatase activity in the corpus luteum but could not find a clear relationship between enzyme activity and embryo survival. Zinc is a ubiquitous element and appears in practically all tissues of the body. Earle and Stevenson (1965) and Pond gt El. (1965) reported the zinc concentration in sow's milk. Earle and Stevenson (1965) found that the zinc concentration of colostrum was higher than later milk and was not influenced by dietary zinc level. Pond gg_§l. (1965) found a higher zinc concentration in milk after 3 weeks of lactation than in milk 1 week post partum. Hansard and Itoh (1968) and Hoekstra gt 2$° (1967) have all shown placental transfer of zinc which was concentrated by the developing fetus rather than the placental membranes. Cassens gt El° (1967) reported that red muscles of pigs had 2 to 3 times as much zinc as white muscles from the same animal. 17 2. Zinc deficiency. a. Swine Since Kernkamp and Ferrin (1953) first described the characteristic skin lesions of parakeratosis in swine and Tucker and Salmon's discovery in 1955 that parakeratosis of swine was caused by zinc deficiency, many eXperimenters at Michigan State, Wisconsin, Cornell and other institutions have extensively studied and described the zinc deficiency syndrome of the pig. Miller §£,§l. (1968b) reviewed the literature on zinc deficiency in swine and found that reduction in growth rate, food intake, and food utilization and the appearance of parakeratotic lesions were symptoms most commonly reported by several workers. Many experimenters have reported a reduction in serum or plasma, and tissue zinc concentrations (Beardsley and Forbes, 1957: Hoekstra 32 al., 1956; Lewis 22 El°v 1957b; Ritchie §£.§l., 1963; Hennig, 1965; Shanklin 33 al.. 1968; Miller §§_§l.. 1968b), and these parameters seem to be sensi- tive indicators of dietary zinc level. Beardsley and Forbes (1957), Whiting and Bezeau (1958), Smith 33 3;. (1960) and Shanklin 33.2l. (1968) have all rem ported a decrease in zinc retention during the deficiency state. Changes in several biochemical parameters of serum have also been observed. Decreases in serum albumin and parallel increases in serum gamma globulin with no change in 18 total serum protein have been reported by Hoefer g3 gl.(1960), Smith g§_gl. (1960a) and Miller g§_gl. (1968b), and Smith (1960a) postulated that this reduction was not due to zinc deficiency per se but resulted from an increased susceptibility to inva- sion by infectious agents. Luecke—g3 gl. (1957). Hoefer gt g1. (1960), Pond g£,gl. (1966a), Roberts g3_gl. (1960), Hoekstra g; 5;. (1967). Miller gt §_1_. (1968b) and Shanklin gt 3;. (1968) have all reported lowered serum alkaline phosphatase activity on diets inadequate in zinc; in addition, Miller g3 gl. (1968b) observed a decrease in liver alcohol dehydrogenase activity. Shanklin g2 gl. (1968) and Miller gt E£° (1968b) reported a decrease in serum calcium and a tremendous reduction in the thymus weight of the zinc-deficient baby pig. Miller also found reduced lymphocyte populations and a tendency for an increased percentage of non-segmented neutrophils which might indicate an active infection somewhere in the pig's body. Hendricks g3 gl. (1966) found that zinc deficiency in the baby pig seemed to cause an increase in oxygen consumption. Zinc deficiency symptoms in the gestating gilt have been studied and are not as severe nor as dramatic as those of the younger pig. Pond and Jones (1964) and Roberts g3 gl, (1962) showed that gilts receiving less than 35 ppm dietary zinc lost weight during gestation. Pond and Jones (196#) also re- ported a reduction in the number, birth weight and postpartum 19 growth rate of the piglets. Hoekstra gEIgl. (1967) observed reduced litter size, birth weight and tissue zinc concentra- tions of the baby pigs from deficient gilts. Hennig (1965) reported similar decreases in growth rate and tissue zinc con- centrations and also found a decrease in the zinc concentra- tions of milk from deficient gilts. The only reports of parakeratosis in the suckling pigs were from the experiments of Roberts gt_gl. (1962) and Hoekstra g§_gl. (1967) at the Wisconsin station. b. Other species. Since 1938 when Todd, Elvehjem and Hart showed that zinc was essential for growth of the rat, few workers studied this relationship until after the description of zinc deficiency in the pig. Macapinlac, Pearson and Darby (1966) have pub- lished an excellent study on the characteristics of zinc deficiency in the rat. The symptoms they observed included anorexia, severe growth retardation, coarse and Sparse hair growth, lymphocytopenia and increased hematocrit values. They reported a reduction in serum alkaline phosphatase activity, an increase in serum glutamio-oxalacetic transaminase activity and no change in liver alcohol dehydrogenase activity. Zinc concentrations of the bone and testis were markedly reduced in the deficient rat. The testis showed tubular atrOphy and degeneration of the germinal epithelium; however, the ovaries exhibited no change. Hyperkeratosis and acanthosis of the 20 skin, esophagus and forestomach were observed along with a de» crease in Spleen weight and an increase in relative weight of the pituitary and adrenals. Forbes and Yohe (1960) demon- strated a reduction in total zinc retention in addition to the dermatitis and reduced growth previously mentioned. Becker and Hoekstra (1968) reported that the liver zinc of rats formed a more stable complex with histidine in de- ficient rats than in control rats. Decreased growth rate and feed utilization and characteristic skin lesions were reported as deficiency symptoms by Hsu g£_gl. (1968). They also ob- served an increase in liver non-protein sulfur compounds and glutathione and an increase in the incorporation of glycine into liver glutathione of zinc deficient rats. Reductions in plasma zinc concentrations were reported by Dreosti g£,gl. (1968) and serum and intestinal alkaline phosphatase activity by Kfoury ggigl. (1968) and Luecke g2 gl. (1968). Luecke stated that the reduction in intestinal phosphatase activity was due to zinc deficiency but the decrease in serum alkaline phosphatase activity was caused by inanition. Testicular atrophy in zinc deficient rats has been re- ported by many workers. In addition to testicular atrOphy, Macapinlac §£.§l- (1968) and Barney ggygl. (1968) reported in- creased RNA catabolism in the zinc deficient testis. Barney further stated that zinc deficiency inhibits the transforma- 21 ,tion of Spermatids to spermatozoa. Bieri and Prival (1966) found reduced phospholipid content in the deficient testis and the atrophy was similar to that caused by a deficiency of aL-tocopherol. Zinc deficiency in pregnant female rats was shown by Hurley and Swenerton (1966) to cause reduced litter size and weight and congenital malformations in 98% of the pups. These malformations of the full-term fetuses encompassed many organs including the skeleton, brain, eye, heart, lung, and urogenital system. Dietary zinc requirement and the zinc deficiency syndrome has been well studied in poultry. Reduced growth, poor feathering and perosis were common deficiency symptoms reported by O'Dell 2£.2£~ (1958) and Roberson and Schaible (1958) in the chick, Kratzer g£,gl. (1958) in the turkey poult, and Fox and Harrison (1964) in the Japanese quail. O'Dell g3 gl. (1958) in the chick, and Fox and Harrison (1964) in the Japanese quail, further reported deficiency symptoms of abc normal respiration, parakeratosis of the esophagus and skin, increased hematocrit and abnormal bone calcification. Zeigler gt 2;. (1964) demonstrated a marked increase in tissue uptake of 65Zn, especially of the bone, liver and duodenum, due to zinc deficiency. Addition of histamine, aspirin, phenylbutazone, cortisone acetate or indomethacin to the diet alleviated the perotic condition of chicks (Nielsen gt gl., 1968) but did not 22 improve growth rate or feathering of the deficient chicks. Zinc deficiency in the hen seems to be more severe than for adults of other species. Blamberg gg'gl. (1960), Klienholz g3 gl. (1961) and Heth g3 gl. (1966a) all reported lowered hatcham bility, impaired skeletal development of the embryos and general weakness in the birds that did hatch. Kienholz also reported impaired growth, frizzled feathers and an accelerated respiratory rate in the deficient, adult hen. Zinc deficiency syndromes similar to those described for the pig, rat and chick have been described for several other species including the calf, sheep, goat, dog, monkey, and man. Reduced growth, food consumption, serum zinc, serum alkaline phosphatase activity and serum albumin with a general dermatitis and alopecia and testicular atrophy have been reported as zinc~ deficiency symptoms of the calf by Ott ggrgl. (1965), Miller and Miller (1962), Miller (1967) and Miller gt gl. (1965). Ott gt gl. (196h) with the lamb, and Miller g2 gl. (1964) with the goat, reported similar deficiency signs to those of the calf. Robertson and Burns (1963) observed marked emaciation, keram titis, retardation of growth and lowered plasma zinc in dogs fed high calcium diets low in zinc. Macapinlac g2 gl. (1967) studied the zinc deficiency of the squirrel monkey and ob“ served reduced serum, heart, liver, pancreatic and splenic zinc concentrations as well as alopecia and unthrifty appearance. 23 Barney g3 gl. (1967) observed parakeratotic lesions on the tongue of the zinc-deficient monkey. A naturally occurring zinc deficiency has been reported by Prasad g2 gl. (1961) in dwarfs in Iran and Egypt. Prasad (1966) reviewed all of his work in this area and reported a syndrome Of dwarfism, hypogonadisn, hepatOSplenomcgaly and anemia whkflimay have been. due to zinc deficiency. Decreased zinc content of plasma, red blood cells and hair and increased 652m turnover rates were reported. Iron supplementation seemed to improve the anemia but not the dwarfism and hypogonadism. These patients were characterized by low dietary intake of animal protein and either geophagia or parasitic infestation and subsequent blood loss, thus aggravating the deficiency condition. 3. Factors influencing zinc requirement. a. Dietary factors. One of the earliest discovered factors influencing zinc requirement was the dietary calcium level. In their original work on zinc deficiency in the pig, Tucker and Salmon (1955) observed that the addition of limestone and/or bonemeal to a diet containing 44 ppm zinc increased the incidence and severity of parakeratosis. A short time later the antagonistic relationship between calcium and zinc was confirmed by many 24 experimenters. Luecke gglgl. (1956, 1957), Hoekstra 22.2;- (1956), Newland g2,gl. (1958), Stevenson and Earle (1956), Bellis and Philp (1957). Lewis g£,gl. (1956, i957a,b), Hoefer gg,gl. (1960) and Berry g£,gl. (1961) all reported that dietary calcium levels above 1% of the diet aggravated the zinc de- ficiency syndrome when compared to diets with less than 0.8% calcium. Increased endogenous fecal zinc excretion due to elevated dietary calcium was reported by Newland gt gl. (1958) and Hansard and Itoh (1968) in the pig and Heth g3 gl. (1966b) in the rat. The reports on the influence of high dietary calcium on zinc absorption are somewhat confusing. Heth gg_gl. (i966b) reported a decrease in zinc absorption in rats fed diets high in calcium and 1% phosphorus but not in those fed diets contain- ing 0.3 to 0.5% phosphorus. Forbes (1964) in the rat and Hoekstra 22.§l- (1964) in the pig both reported decreased zinc absorption due to high dietary calcium. Cabell gt gl. (1965) observed that high levels of either calcium or phosphorus pre~ vented normal intestinal absorption of zinc and their effects were additive in the rat. To further confuse the issue, Forbes and Iohe (1960) reported that the apparent absorption and urinary excretion of zinc by rats were not influenced by in.- creased dietary calcium and perhaps even more confusing is the (report of Berry gt gl. (1961). They reported that high calcium added to a low zinc diet for the pig caused reduced blood, 25 plasma and tissue 65Zn activity: however, high calcium added to a zinc adequate diet increased blood and tissue zinc activity. In previous studies with the pig, Lloyd and Bell (1958) re- ported that increased dietary calcium on zinc adequate diets caused an increase in zinc absorption, and Hennig (1965) stated that in some cases calcium and zinc effects were synergistic and in other cases antagonistic. The variation in the reported effects of dietary calcium on zinc metabolism was partially explained by Byrd and Matrone (1965) when they reported that .the detrimental effect of high dietary calcium on zinc absorp- tion was dependent on the presence of phytate. They further demonstrated that high calcium enhanced the complexing of zinc with phytate at low zinc levels but decreased the complexing at high zinc levels. Hansard and Itoh (1968) studied the influence of limited dietary calcium on placental transfer of zinc in the sow and found that zinc was more accessible for placental transfer when (dietary calcium was 0.3% as compared with 0.7%. Heth g2 El! (1966a) and Kienholz g§,gl. (1961) reported an antagonistic relationship in the chick between calcium and zinc while O'Dell g§,g;. (1958) stated that the antagonism was not as pronounced in the chick as in other species. Spencer gt_g;. (1965) did not find any calcium-zinc antagonism during low and high cal- cium intake in man. 26 Other minerals have been studied to examine their in- fluence on zinc metabolism. An antagonistic relationship be- tween cadmium and zinc has been reported by Supplee (i963), Gunn g§_g;. (1961) and Parizek (1960). Supplee reported that cadmium increased the severity of zinc deficiency in chicks but this could be overcome by large quantities of zinc. Gunn 22,5l. (i961) and Parizek (1960) observed that cadmium produced a rapid necrosis of the testes and accessory sex glands in rats which could be prevented by massive doses of zinc acetate and Parizek postulated that cadmium disturbed the physiological function of zinc and not the absorption and transport of zinc. Powell g£,gl. (1967) contradicted Parizek when he reported that 350 ppm cadmium greatly reduced the absorption of zinc from the gut of ruminants but did not alter tissue retention of zinc. Furthermore, Gunn and Matrone (1966) reported that cadmium treatment caused an increase in liver and testis zinc concen- tration of normal rats. Hiers gt gl. (1968) did not find any 65 effect of cadmium on Zn or dry matter secretion or reabsorp- tion in the small intestine of calves, and Pond g£.gl. (1966) concluded from work with the pig that cadmium was not an . antagonist of zinc. Dietary copper levels of 125 or 250 ppm were reported by Ritchie g§,g;. (1963) and Hoefer g2_gl. (1960) to reduce the incidence and severity of parakeratosis, hence a zinc sparing effect: however, Gipp g£_g;. (1967) could find 27 no conclusive evidence for any copper-zinc interaction. Lewis 33.21. (1956) reported that additions of monosodium phosphate had no effect on bodyweight gain but reduced the severity of the skin lesions in zinc-deficient pigs. Published work by Becker and Hoekstra (1966) showed increased zinc absorption caused by additional vitamin D; however, they concluded that this phenomenon was a homeostatic response to the increased need for zinc which accompanied enhanced skeletal growth rather than a direct effect of the vitamin. Lease and Williams (i967a) reported that the addition of #50 ppm of magnesium to a sesame meal ration containing strongly bound zinc decreased the availability of added zinc. This effect was not observed with other meal diets or casein. The dietary source of amino acids has been demonstrated to alter the utilization of zinc and many other minerals and the presence of phytate seems to predicate decreased utiliza- tion. O'Dell and Savage (1960) reported that zinc in diets containing isolated soybean protein was less available to the chick than zinc from milk protein diets. Smith ggpgl. (1961) pr0posed a zinc requirement for the baby pig of #6 ppm on soy protein and later reported (Smith g3 g1., 1962) that soy pro- tein increased the zinc requirement above the one for milk protein. A few years later, Shanklin g3 gl. (1968) reported a zinc requirement for the baby pig of between 14 and 20 ppm 28 with a casein diet or less than one-half the requirement re- ported by Smith. Other reports of a higher zinc requirement with soy protein as compared to casein or egg white protein are published by Forbes (1964) in the rat and O'Dell and Savage (i960) and Neilsen g3 gl. (1966a) in the chick. The influence of protein source on zinc availability seems to be related to the phytate content of the protein source. Oberleas g£,gl. (1962) demonstrated that additions of phytic acid to animal protein diets produced symptoms of parakeratosis and growth depression typical of plant diets. O'Dell gt gl, (196u) reported that the addition of phytic acid to casein-gelatin diets decreased the availability of zinc: however, preformed calcium phytate had no effect (O'Dell and Savage, 1960: O'Dell g£.gl., 1964). Likuski g£_gl. (196“) further demonstrated that decreased zinc availability resulted from phytic acid additions to diets containing either casein or crystalline amino acids. Lease and Williams (1967b) did not observe any relationship between the phytate content and zinc availability of different oil seed meals, but Lease (1967) in another paper did observe differences between the oil seed meals in the solubility of the zinc phytate complex, hence availability for absorption from the gut. The detrimental effect of elevated dietary calcium has been reported to be de- pendent on the presence of phytate. Byrd and Matrone (1965) 29 demonstrated that calcium enhanced the absorption of zinc into phytate at wide zinc-calcium ratios; however, at narrow ratios, calcium decreased the absorption of zinc into phytate which ex- plains the previously reported influence of dietary calcium level on zinc absorption from the gut. Later, Lease and Williams (1967b) reported that calcium and magnesium had no effect on zinc binding by phytate in certain oil seed meals. In 1112 demonstrations of a calcium-zinc-phytate interrelationship have been reported by Forbes (1964), Likuski and Forbes (1965) and Oberleas ggpgi. (1966) in the rat, O'Dell g£_gl. (1964) in the chick, and Oberleas g£_gl. (1962) in the pig. Zinc is not the only mineral bound by phytate at intestinal pH. Maddaiah g£_gl. (1964) demonstrated that sodium phytate formed complexes with metals in the following decreasing order: Cu++, Zn++, Ni++, Co++, Mn++, Fe+++, and Ca++. Many compounds have been added to diets to try and overa come the influence of phytate on zinc availability. O'Dell gt_gl. (1964) and Nielsen g3 gl. (1966a,b) in the chick, Vohra and Kratzer (1966) in the turkey, Oberleas g£,gl. (1966) and Forbes (1961) in the rat and Smith gg'gl. (1962) in the pig observed that addition of ethylenediaminetetraacetic acid (EDTA) to the diet improved the availability of zinc in diets con- taining phytate but not in phytate-free diets. They postulated that zinc was preferentially bound to EDTA and was soluble in 30 this form; however, Powell gt gt. (1967) found no benefit of EDTA additions to the diet of goats or calves. Nielsen gt gt. (1966b) reported that in addition to EDTA, other synthetic chelating agents, EDDA, HEDTA, DTPA, and a natural chelating agent, cysteine, alleviated all zinc deficiency symptoms while DHEG, IDA, EBONTA, xanthurenic acid, kynurenic acid, anthranilic acid, glutamic acid, cystine and tryptcphan had no effect on the deficiency symptoms. Vohra and Kratzer (1966) studied the effects of phosphate on zinc binding, and found that in turkey diets containing 15 ppm zinc, growth was superior when phosphorus was supplied by sodium hexametaphosphate, sodium tripolyphosphate, sodium acid pyrophosphate or sodium orthophosphate as compared to dicalcium phosphate and sodium or calcium phytate. Moreover, dietary zinc was more available from EDTA and DTPA than the phosphate compounds. Some benefit in overcoming the zinc-phytate interaction was demonstrated with lactose additions by Forbes (1961, 1964) and Smith gt gt. (1962) and with autoclaving the diet by Smith 22.El° (1962), Smith gt gt. (1960b) and Nielsen gt gt. (1966b). b. Other factors. Several other variables besides diet have been reported to influence the zinc requirement. Pond and Hoefer (1961) from Cornell and Michigan State Universities, respectively, 31 exchanged swine diets and discovered that Michigan State could more easily produce parakeratosis than Cornell. These diets were similar in their nutrient levels and varied only in the source of the feed ingredients. Pond gt gt. (1964) reported subsequent studies in which the incidence of parakeratosis was greater with diets using corn from Illinois rather than corn from New York. Age differences have been reported and apparently zinc requirement decreases with increasing age. Miller gt gt. (1968) in the young calf reported that 2% month old calves ab- sorbed a larger percentage of ingested zinc from a zinc-adequate diet than did 4% month old calves; however, no difference in absorption of zinc from a zinc-deficient diet was observed. Hoekstra gt gt. (1967) and Pond and Jones (196a) fed low zinc diets, known to produce parakeratosis in growing swine, to gestating gilts and reported a slight growth reduction as the only deficiency symptom while Roberts gt gt. (1962) and Hennig (1965) did not find any deficiency symptoms on similar diets. Furthermore, we have experienced difficulty at this station in producing parakeratosis if the initial weight of the pigs is above 15 to 20 k110grams. Strain and Pories (1966) have reported that hair zinc is a reliable indicator of zinc status in humans and observed that hair from women was much higher in zinc than hair from men. This difference might indicate a higher metabolic activity of zinc in men than women. Miller 32 gt gt. (1969) reported that 45 ppm zinc appeared adequate for the female baby pig but not the male, and the parakeratotic lesions were more severe in the males. c. Toxicity of zinc. The need to add zinc to the diets of most animals has been well established, but it is also important to know the conse- quences of supplying excessive dietary zinc. Dietary zinc concentrations above 1000 ppm interfered with copper and iron metabolism and caused an anemia to develop which could be corrected by high cOpper and iron additions (Magee and Matrone, 1960; VanCampen, 1966: Smith and Larsen, 1946; McCall gt gt,. 196ia,b; and Magee and Spahr, 196s). Decreased growth rate and feed utilization are other symptoms of zinc toxicosis reported by Brink gt gt. (1959), Magee and Matrone (1960) and Magee and Spahr (1964). In addition, arthritis, congestion of the mesentery, extensive hemorrhage in the axillary spaces, gas- tritis, catarrhai enteritis, and hemorrhage in the ventricles of the brain, lymph nodes and spleen were other toxic symptoms observed by Brink gt gt. (1959). Dietary zinc concentrations of 4000 ppm were reported by Schlicker and Cox (1968) to cause 100% resorption of rat fetuses when fed beginning 21 days be- fore breeding. Roberson and Schaible (1960) reported extensive mortality in chicks fed diets containing 3000 ppm of zinc carbonate. 33 C. Sex Differences and Nutrient Interactions. Differences between the sexes in growth rate and conver- sion of food to liveweight gain are well documented. Bruner gt gt. (1958) summarized data from the Ohio Swine Evaluation Station and reported that barrows gained significantly faster than littermate gilts. Since then, many other workers includ- ing Lucas and Calder (1956), Bowland and Berg (1959), Mul- holland gt gt. (1960), Baker gt gt. (1967), Brooks (1967), and Hale and Southwell (1967) have reported this same difference in growth; however, Hale gt gt. (1968) did not find any difference in growth rate between barrows and gilts. Winters gt gt. (1942) compared boars to barrows and observed an advantage in growth rate for the boars. They postulated that this advantage in growth rate was largely due to differences in skeletal growth and fat deposition with boars having more bone and less fat. Prescott and Lemming (1964) reported that barrows gained faster than boars, but most other workers have supported Winters (Wag- ner gt gt., 1963; Charette, 1961; Cahill gt gt.. 1960: Teague gt gt., 1964; Blair and English, 1965; and Hines, 1966). McCampbell and Baird (1965) found no difference in growth rate between boars and barrows, but observed that they both gained faster than gilts. These findings are supported by Hines (1966), Blair and English (1965) and Cahill gt_gt, (1960). Hines (1966) observed similar growth rates for intact gilts and spayed gilts. 34 Many workers have reported lower daily feed consumption for boars than either barrows or gilts and boars were more efficient in converting food to liveweight gain (Hines, 1966; Charette, 1961: Wagner gt gt., 1963: and Teague gt gt., 1964). McCampbell and Baird (1965) observed similar feed/gain ratios for boars and barrows while gilts were 4.5% more efficient. In addition, Blair and English (1965) found that gilts consumed less feed than barrows or boars; however, boars still had superior feed/gain ratios. Cahill gt gt. (1960) did not find any difference in feed/gain ratios between gilts and boars. Gilts were reported to have lower feed/gain ratios than barrows by Lucas and Calder (1956), Baker gt gt. (1967) and Hale gt gt. (1968) while Hines (1966) and Bruner gt gt. (1958) found no difference. These reports clearly illustrate the problems in trying to evaluate feed efficiency and the variation from station to station and year to year. Many workers who reported growth differences evaluated the carcasses and generally agreed that intact animals dis- played superior carcasses to those of castrates. Boars had thinner backfats and greater percentage of lean cuts than gilts which in turn were trimmer and meatier than barrows (McCamp- bell and Baird,1965; Zobrisky gt gt.. 1959: Hammond and Murray, 1937; Blair and English, 1965; Hines, 1966; and Charette, 1961). In studies comparing only two sexes, Teague gt gt. (1964), 35 Plimpton gt gt. (1967), McMeekan (1940), and Prescott gt gt. (1964) reported that boars were leaner and more muscular with a higher percent of bone than barrows while Bruner SE.&$° (1958), Brooks (1967), Hale and Southwell (1967), Baker gt gt, (1967), Hale gt gt, (1968), Babatunde gt gt. (1967), and Plank and Berg (1963) all reported that gilts yielded superior carcasses to barrows. Plank and Berg suggested that the sex differences in carcass composition probably arise from metabolic differ- ences which influence the relative production of fat and lean tissue. They did not find any difference in dry matter digesti- bility and concluded that a differential utilization of nutrients occurs after digestion rather than from differential digestion and/or absorption from the gut. Hines (1966) and Zobrisky gt gt. (1959) reported that spayed gilts yielded carcasses similar in backfat and percent lean cuts to those of barrows. Sex differences in several biochemical parameters of blood and other tissues have been reported. Brooks (1967) reported that the intramuscular and depot fat of gilts contained a higher percentage of linoleic acid and a lower percentage of palmitic acid than corresponding tissue of barrows. Babatunde gt gt. (1967) observed similar differences in linoleic acid content and further reported a higher average carcass ash con- tent for gilts than barrows. Koch gt gt. (1967) observed that the linoleic acid content of backfat decreased in the order of 36 boars > gilts > barrows > spayed gilts. In addition, barrows had significantly higher stearic acid concentrations than gilts, and spayed gilts had greater total saturated fatty acid concentrations than the other sexes. Boars were found by Fausch gt gt. (1968) to have lower serum cholesterol and higher adipose tissue cholesterol concentrations than gilts or barrows, and they also observed that barrows had higher hepatic cholesterol levels than boars or gilts. Bruell £3.2l- (1962), however, observed higher serum cholesterol levels in male mice than in female mice. Horsbang (1959) reported that 1 to 5 month old female calves had higher erythrocyte volume, erythrocyte count, and hemoglobin concentration than male calves of the same age. Barrows were shown to have higher total serum protein,,¢?-and )’-globulin levels than gilts while gilts had higher albumin and Js-globulin levels than barrows (Kotik, 1966). Kolataj (1961) observed that male chicks had higher sulfhydryl (SH) group levels than females and thought the SH groups might be related to the inheritance of biochemical traits. Tanabe and Wilcox (1960), also with chicks, reported higher serum alkaline phosphatase activity in the growing male up to 14 weeks of age than the female. From 18 to 34 weeks of age the activity was higher in the female, and the change was attributed to the requirements for egg pro- duction in the hen. Dreosti gt gt. (1968) found a higher plasma 37 zinc concentration in prepubertal male rats than pregnant fe- males on identical diets; however, this difference may be caused by other factors, such as age and pregnancy, rather than sex. Heretofore, I have described simple sex differences, but several workers have reported interactions between sex and nutrient levels in the diet. Baker 22.2l3 (1967) reported that rate and efficiency of gain were maximized at dietary protein levels of 12% in barrows and 14% in gilts, and maximum carcass leanneaswas attained at protein concentrations of 14% in barrows and 16% in gilts. Prescott and Lemming (1964) observed that the growth rate of boars was retarded when switched from a high dietary protein level to a lower level while barrows were un- affected by the reduction in protein. A few years later, Prescott and Lemming (1967) reported a definitely greater re- sponse in growth rate and muscle mass in boars than in barrows when dietary protein was increased. Pond and VanVleck (1965), with the rat, and Siegel and Wisman (1962), with the chick, compared intact males to intact females and reported a greater response in growth rate to increased dietary protein in males than females, thus indicating a higher protein requirement by the males. Robinson (1964) found that both boars and gilts responded more to high protein diets than did barrows, and he concluded that boars and possibly gilts apparently have higher 38 protein requirements than barrows. Piatkowski and Jung (1966) published nitrogen retention values that supported the conclu- sions of Robinson. They reported that nitrogen retention was 28% greater in boars and 11% greater in gilts than barrows on isonitrogenous diets. The interaction of sex and dietary energy level is not as clear cut as that of dietary protein. Lucas and Calder (1956) and McMeekan (1940) reported that the fat content of gilts was reduced more by limited feeding than barrows; however, Hines (1966) observed that when gilts and barrows were restricted to 80% of gg libitum intake, the back- fat of barrows was reduced but that of gilts was not affected. Beacom (1964) demonstrated that the growth rate of barrows was more adversely affected by dietary restriction than that of gilts, and Hines (1966) reported that when barrows and gilts were restricted to 5 lbs. of feed per day, gilts outgained the barrows. Sex differences in the utilization of minerals have also been observed. Kinnamon and Bunce (1965) reported that female rats were more tolerant of high levels of molybdenum and zinc than were males. Addition of molybdenum to high zinc diets caused increased bone retention of zinc in males and reduced retention in females. The data of McCall gt gt. (1961) also suggested that male rats were more susceptible to zinc toxicity than female rats. Small amounts of cadmium in the drinking 39 water of rats were reported by Schroeder (1964) to cause hyper- tension and the incidence and severity was greater in females than males. Strain and Pories (1966) proposed that hair zinc concentration is an adequate indicator of zinc status in man. They observed higher hair zinc values in females than males which might suggest a higher zinc requirement for the male. Miller gt gt. (1969) observed more severly reduced growth rates, serum zinc concentrations, and serum alkaline phospha- tase activities in male baby pigs than in females when both sexes were fed diets containing less than 45 ppm of zinc. Furthermore, the incidence and severity of parakeratosis were greater in the male, and these data strongly suggested a higher zinc requirement for the male. Swenerton and Hurley (1968) obtained data with the rat which also suggested a higher zinc requirement for the male. Females fed diets con- taining 40 ppm of zinc grew and developed normally while long term testicular degeneration was observed in males re- ceiving 60 ppm of zinc in their diet. In addition, deficiency symptoms were more severe and appeared sooner in the males than the females. III. EXPERIMENTAL PROCEDURE A. Introduction Five experiments, involving 97 boars, 97 gilts, and 62 barrows, were conducted to examine the effect of sex on the mineral requirements of developing swine. These experiments were: Experiments 1 & 2. Influence of sex on the calcium requirement of de- veloping swine. Experiments 3, 4 & 5. Influence of sex on the zinc requirement of develop- ing Buineo Yorkshire, Hampshire and York-Ramp crossbred pigs were randomly allotted from weight, sex and litter outcome groups to the experimental treatments. All pigs had free access to feed and water and were weighed at two week intervals. Average daily gain, daily feed consumption and gain to feed ratios were compared in all experiments. Composition of the diets are shown in tables 1. 2 and 3. The 16% protein diets were fed to 50 kg. bodyweight and the 13% protein diets from 50 to 100 kg. bodyweight. 40 41 Table 1. Composition of the diets (Experiments 1 & 2). Level of Protein, % 16 13 Level of Calcium, % 0.6 0.9 1.2 0.6 0.9 1.2 Ground shelled corn 79.6 78.6 77.7 86.8 85.9 85.0 Soybean meal (50%) 17.7 17.8 18.0 10.4 10.5 10.6 Ground limestone 0.7 1.5 2.3 0.7 1.5 2.2 Dicalcium phosphate 1.0 1.0 1.0 1.1 1.1 1.2 Trace mineral salt (HiZn) 0.5 0.5 "0.5 0.5 0.5 0.5 VATM premixa 0.5 0.5 0.5 0.5 0.5 0.5 Total 100.0 100.0 100.0 100.0 100.0 100.0 Chemical Analygis Crude protein, % 16.5 16.6 15.9 13.3 13.3 13.? Calcium, % 0.69 0.87 1.12 0.65 0.88 1.24 Phosphorus, % 0.48 0.44 0.51 0.50 0.48 0.50 Zinc, ppm 121 114 110 105 110 100 a The vitamin antibiotic premix supplied the following vitamin levels per kilogram of feed: vitamin A, 3300 IU; vitamin D, 660 IU; riboflavin, 3.3 mg.; pantothenic acid, 13.2 mg; niacin, 17.6 mg; B1 , 19.8 mcg; choline chloride, 110 mg. The premix also furnished 40 gm. of zinc, 6.6 gm. of peni- cillin and 33 gm. of streptomycin sulfate per 1000 kg. of feed. L12 Table 2. Composition of the basal diet (Experiments 3, 4 & 5). Level of protein, % 16 13 Ground shelled corn 79.1 86.3 Soybean meal (50%) 17.8 10.5 Ground limestone 1.1 1.1 Dicalcium phosphate 1.0 1.0 Trace mineral salt (LoZn) 0.5 0.5 Vitamin-antibiotic premixa __9a2. __2a2 Total 100.0 100.0 a Vitamin and antibiotic levels were similar to those in table 1 except that 220 IU of vitamin E per kilogram of feed were added in experiment 5. Table 3. Chemical analyses of experimental diets. Experiment 3 4 5 Zinc level, ppm 30 60 90 30 50 70 30 70 Calcium, % 0.75 0.73 0.64 0.71 0.71 0.72 0.73 0.71 Phosphorus, % 0.46 0.47 0.44 0.42 0.42 0.42 0.43 0.42 Zinca, ppm 22.4 53.2 80.3 28.7 48.1 69.8 30.5 72.1 a Supplemental zinc was added as zinc oxide. B. 43 The experiments. 1. Experiment 1. Twelve boars and 12 gilts of Yorkshire breeding from four litters by a common sire were randomly assigned to three dietary calcium levels (0.6%, 0.9%, or 1.2%) with pen replica- tions. Blood samples were taken from the anterior vena cava initially, at 4, 8, and 12 weeks and upon completion of the trial for the determination of serum calcium, phosphorus and zinc concentration and serum alkaline phOSphatase activity. Elevated dietary calcium was shown in the rat to cause an in- crease in total carcass protein (Ali and Evans, 1967a); therefore, we decided to examine the carcasses of these animals. Upon completion of the feeding trial all animals were slaughtered at the University Meats Laboratory, and backfat, length, loin eye area at the 10th rib, percent ham and loin and percent lean cuts were determined as oulined by the Pork Carcass Evaluation Committee (1952). Also at this time, the right ham was saved for future chemical analysis. The right femur and fourth metacarpal were retained for subsequent physical and chemical analysis and the first lateral phalanx and turbinates were taken for histological examination. 2 . repayment 2.. Twentyefour boars and 24 gilts of Yorkshire and Hampshire breeding were randomly assigned to the same dietary calcium 44 treatments as experiment 1. Blood samples were not obtained in this experiment. Upon completion of the trial, all animals were slaughtered at a commercial packing plant and the fourth metacarpal and the first lateral phalanx from the right front foot were removed for strength, density and mineral analyses. The turbinates were removed as in experiment 1 for mineral and histological examination. 3. Experiment 3. Sixty-three pigs of primarily Yorkshire breeding were assigned in a 3 x 3 factorial design from sex and weight out- come groups to 30, 60, or 90 ppm of dietary zinc with 7 pigs per experimental lot. The boars were randomly selected at 4 weeks of age and the remaining boars were castrated to supply the barrows. Blood samples were withdrawn from the anterior vena cava on four occasions(initially, 4 and 8 weeks and upon termination of the experiment) for serum zinc and alkaline phosphatase determinations. Upon completion of the trial, the deficient pigs were fed a zinc adequate diet and returned to the swine farm inventory. 4. Experiment 4. Seventymtwo animals of both Yorkshire and Hampshire breeding were assigned to 30, 50 or 70 ppm of dietary zinc in a similar manner to those of experiment 3. Again boars were 4.x i1»..- .|\\ a 45 selected at 4 weeks of age, and blood collections were made as in the previous experiment. 5. EXperimentg5. Forty-eight pigs were allotted to two dietary zinc levels (30 or 70 ppm) and the experiment was conducted in a similar manner to experiments 3 and 4. The same criteria were used to evaluate this experiment as the previous two experiments. Chemical analytical procedures. 1.321229 Upon withdrawal, the blood was placed in acid washed centrifuge tubes, allowed to clot and centrifuged at 550 g. for 15 minutes. The cell free serum was then harvested and placed in acid washed vials. Aliquots were removed for immediate determination of serum alkaline phosphatase activity and the remaining serum was frozen at -10° C for subsequent mineral analysis. Serum alkaline phosphatase activity was determined by the Sigma procedure (Sigma Technical Bulletin, 1963). Serum calcium and zinc concentrations were determined by atomic absorption spectrophotometry (Jarrell-Ash MOdel 82u516 spectrophotometer equipped with a Hetco total consump- tion burner and an air-hydrogen flame) as described by Ullrey gt gt. (1967). For the calcium determination, serum proteins 46 were precipitated with TCA and the resulting protein free supernatant was diluted with 10,000 ppm SrCl2 to suppress phosphate interference. The serum was diluted with deionized water for zinc analysis. Absorption wavelengths of 4227 R and 2138 2 were used for calcium and zinc, respectively. After precipitation of the serum protein with TCA, serum inorganic phosphorus was determined colorimetrically by the Fiske- Subbarow method (1925) and read on a Beckman DU spectrophoto- meter at a wavelength of 700 mm. 2. tggg. In experiment 1 the right femur was removed and cleaned of adhering connective tissue and periosteum and placed in an air tight plastic bag. After autoclaving the right front foot for 20 minutes the fourth metacarpal and first lateral phalanx were removed, cleaned free of tissue and frozen at ~20o C in both experiments 1 and 2. Strength and density tests were made on the femur in experiment 1 and the fourth metacarpal in experiment 2. Specific gravity was determined according to the following formula: weight in air Specific gravity 3 weight in airoweight in water In experiment 1 strength of the right femur was determined using a Tinius-Olsen universal testing device1 with accuracy 1TiniusmOlsen, Willow Grove, Pennsylvania. 47 of i 1 kilogram. An Instron Testing Instrument, Model-TT CML , equipped with a FM-compression load cell having 200 kg. full scale, was used to test the strength of the fourth meta- carpal in experiment 2. Crosshead speed of 0.2 cm/min. and chart speed of 2 cm/min. and a metal collar of appropriate diameter to support the bone were used in testing the meta- carpal. The formulas for calculating the various strength characteristics are those described by Miller gt gt. (1962) and are as follows: Maximal bending moment, M = W1/4 Moment of inertia, I =:7r(BD3-bd3)/64 Maximal stress, 8 = MD/ZI Elasticity, E = W13/48Iy max imal load 22 II distance between the fulcra H il outer and inner horizontal diameter 0 a 0‘ n l outer and inner vertical diameter ‘<: O {I} deflection at center of bone when load W is applied The snouts were removed from the carcasses and a 1 centi~ meter section of the turbinates was removed from the location of the first premolar and fixed in 5% formal-saline for hisu 2 Instron Engineering Corporation, Canton, Massachusetts. 48 tological examination by a histopathologistB. A lateral phalanx was also sectioned longitudinally at this time for examination of the epiphyseal plate. The remainder of the turbinates in experiment 2 were used for mineral analyses. The fourth metacarpal in experiment 1 and the first lateral phalanx and the turbinates in experiment 2 were cut in small pieces on a power band saw and extracted 24 hours with abso- lute alcohol and 24 hours with anhydrous ethyl ether in a Soxhlet extractor to remove the fat and moisture. The dry, fat-free bone was ashed in a muffle furnace at 700° c for 18 hours and the percent ash was calculated from the following formula: weight ashed bone x 100 weight of dry, fat-free bone’=% 33h on a dry, fat-free b331s Approximately 300 mg. of powdered bone ash were dissolved in 5 ml. of 6N HCl and diluted to 100 ml. with deionized water for subsequent mineral analysis. The ash solutions were dim luted 1:100 with an aqueous solution of 10,000 ppm SrClz and calcium was determined from these dilutions by atomic absorp» tion spectrophotometry as previously described for serum. Phosphorus was determined by the colorimetric method previously 3 Dr. Kenneth Keahey, Animal Diagnostic Laboratory, Michigan State University, East Lansing, Michigan. 49 described for serum inorganic phosphorus. Bone calcium and phosphorus were expressed both as a percent of the ash and as a percent of the dry, fat-free bone. 3. Egg. The skinned, boneless right ham and all of its fat trim were ground five times to insure homogeneity, twice through a 1/4 in. plate and three times through a 5/64 in. plate. Approximately 100 gm. were stored in plastic containers and frozen at -10° C for later moisture, fat and protein determina- tions. After thawing for several hours approximately 5 gm. of sample were weighed into disposable aluminum dishes and dried at 1100 C for 24 hours for moisture determinations. The dried sample was then extracted with anhydrous ethyl ether for 3 to 4 hours in a Goldfisch Fat Extractor to determine the fat con- tent: one gram of fresh tissue was analyzed for protein con- tent by the micro-Kjeldahl technique. Moisture, fat and pro- tein were expressed as a percent of the fresh weight. 4. Eggg. Approximately 2 gm. of air dry feed were digested first in 50 ml. of concentrated nitric acid and second in 7 m1. of concentrated perchloric acid in a wet ashing procedure. The digestion flask was heated to near dryness, cooled and diluted to 100 ml. total volume with deionized water. Calcium, phos- D. 50 phorus and zinc determinations were made as previously out- lined for serum and bone. Crude protein was determined by a micro-Kieldahl technique 0 Statistical Analysis. All data were subjected to analysis of variance, and treatment differences were determined by application of the multiple range test of Duncan (1955). Simple correlations were also determined as described by Snedecor (1956). A. IV. RESULTS AND DISCUSSION Influence of Sex on the Calcium Requirement of Developing Swine. 1. Experiment 1. Pig performance and carcass data are presented in table 4. Gilts gained slightly faster than boars from 0 to 8 weeks but for the entire experiment boars grew faster and were slightly more efficient in converting feed to liveweight gain than gilts. Daily gain was depressed in the boars on 1.2% dietary calcium and in gilts on both 0.9% and 1.2% calcium. Gain/feed ratios were slightly depressed by high dietary calcium. Boars had longer carcasses and carried less backfat than gilts, but gilts had significantly larger loin eye areas (P < 0.01). Boars and gilts had equivalent ham and loin and lean cut percentages. Dietary calcium level did not signi- ficantly influence carcass measurements. The sex differences in performance and carcass measurements observed in this ex- periment show the same trends as those reported by Hines (1966) but are of a much lower magnitude. Water, ether ex- tract, and crude protein content of the whole ham did not differ due to dietary calcium level or pig sex. These findings differ from the reported finding in rats by Ali and Evans (1967) that increased dietary calcium caused an increase in whole carcass protein. Serum mineral concentration and enzyme activities are 51 52 .86 v. a 8 :36 v 5 .28.» .93» teoa 5:3 not...» fiefieaucwam e .36 v a .5 ”966 v .5 83.» 25 t2; use. 88.8 353353 e .52: on» me She mes-gum « $6 26 , 36 36 e5 e5 .2; 56a e6” .2; w a .5398 .36 86 N66 36 $6 6.3 92 £3 «.3 66a 6.8 u Jess... teen 96 R6 36 $6 RS in... 98 new 6.8 game a .32.: «"3 R6 26 2.6 R6 RR «6... 66m «.8 :6“ 66m u .38 53 $6 36 R6 R6 «.3 «.3 6.3 «.3 6.3 n6: a .53 R. 5m R6 86 3.6 no; exam... chem eecR NR RR new «.8 .8... as 53 R6 R6 $6 2.6 3K «.8 eS ~66 e.~w is .8 .683 3.6 3.6 R6 86 8.6 R6. 96 £6 36 36 .3 6.3.3 awn-fig S6 86 86 8.6 R6 R6 R6 R6 R6 R6 estate 86 $6 86 36 8.6 8.6 26 86 9.... 8.6 .3 6.38%.... See 38 36 86 3.6 86 $6 $6 2.6 $6 2.6 R6 .3 .55 as. 3...... 86 R6 R6 86 86 R6 .26 $6 $6 86 .9. .84 J1 Re 86 36 36 86 36 gene SR6 $6 nR6 an 6 .92 .84 .8. .46 R6 R6 R6 36 m 98 m6... use £3... dfia R6 86 R6 R6 6.3 T3 I: as .23... 133 6.5 s new new .9: sum“. .3 e6 6 a .8338 . cagedamm madam Rom in usage son.“ .uaaosohuwdos and use .3353 use cosmomaoamwm no big .3 names 53 summarized in table 5. Increasing dietary calcium caused a significant increase in serum calcium at 8 and 12 weeks (P < 0.01) and the differences at 4 and 16 weeks approached significance (P < 0.08). Serum inorganic phosphorus was sig- nificantly depressed by increased dietary calcium at 4 and 12 weeks (P < 0.05) but was not altered at 8 and 16 weeks. Serum zinc at 16 weeks was significantly decreased by 1.2% dietary calcium (P < 0.01). No sex differences or sex 1 treatment interactions were observed for any of the serum minerals. Initial serum alkaline phosphatase activity was significantly higher in the gilts than the boars (P < 0.04) which differs from the work of Tanabe and Wilcox (1960) who found higher activity in the male chick than the female. Increased dietary calcium caused a significant increase in serum alkaline phosphatase activity at 4 and 8 weeks (P < 0.05) which became nonnsignificant at 12 and 16 weeks. This in- crease in alkaline phosphatase activity coupled with the decrease in serum phosphorus suggests the possibility of an induced phosphorus deficiency on 1.2% dietary calcium. The calcium to phosphorus ratio present in the 1.2% calcium diet (2.4:1) has been shown by many workers including Chapman gt 2;. (1962). Combs 93 9;. (1962a.b, 1966) and Ziminerman 23; a_]._. (1960. 1963) to be detrimental to growth and to interfere ‘with phosphorus absorption from the gut. .86 v 6 .. 2666 v .5 83”.. 5.... fl. 55 5......» 585.853» . .86 v a .6 2666 v a 55.» .38 5.... 5.. 5......» 55555.36 6 .86 v m o. 2666 v e 55.» .93.. .55 55. 5......» 685.8868 . ..»«6.6.v.5 .6 ”Am... v .6 ...H.> .3. ....H a... ..6...».5H........».6 n .86 v a 5 ”$66 v .c .66.. 5.3 55 56....» 2.5.85»... . . .56: .3571 you copauondH Hososnohpfluun Ho 1‘ H u add: a N . v .526 23 no you: gunman H 54 66.6 65.6 .\ «NA. 66.6 6.6 6.6 6.6 6.6 5.6 5.6 .x..: 66 65.6 55.6 66.6 66.6 6.6 6.6 6.6 6.6 6.6 6.6 .2... 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H...H.H 7n: SQ»: .5301». Egon Ham“ N.H non Mon Now n.D Mon Rafi—«wapg 6.30m .6H.» x.6 . KKG o 023065": m .J #:0369093 scum braved 2520 vs.» 30.60.63.583 H3053 Erna» mo gm .n candy 55 Data from the metacarpal, femur and turbinates are pre- sented in table 6. The ash, calcium and phosphorus content of the fourth metacarpal was not affected by either dietary calcium level or pig sex. Bears had significantly heavier femurs than gilts (P < 0.01) and 1.2% dietary calcium caused a decrease in femur weights of both boars and gilts; however, this difference is probably a function of decreased body weight. Specific gravity of the femur was constant for all treatments. Strength of the femur as indicated by breaking strength, bending moment. moment of inertia, maximal breaking stress and Young's modulus of elasticity decreased with in. creasing dietary calcium in boars; however, in gilts breaking strength and bending moment were slightly decreased on the high calcium diet and moment of inertia was drastically re- duced causing an increase in maximal breaking stress and modulus of elasticity. Gilts had significantly greater values for maximum breaking strength and modulus of elasticity than boars which indicates the bony matrix of giltsvas stronger than that in boars. Figure 1 shows the load-deflection curves for the femurs in experiment 1. The femurs from the boars were longer than those from the gilts which eXplains the greater deflection at breaking for the boars than gilts. The load-deflection curves indicate that the femurs from the jpigs fed 1.2% dietary calcium are weaker than those on the ....6 v m .. ”A6....v..6 .....> ..... .H. n... ......» .H........».6 . ...6 v m .6 26.6 v .6 .3... 2.. .2... 5... 5....» 2.53.8»... . .86 v m .. :6... v .6 o...» .9... 5... 5....m 5.5.8836 . .935. n. 6 $96.36.... N a 5.66de n m Jam“? bob u N .Haahoauu N .nuoa on» Ho .0990 unuunupm a 56 6... .6... 6... 6.... 6... . .6 . .82.... .58... ..6 6... 6... .N6 8.. 6... 6... 6... 6... 6... 58...... .58.... 6 6. 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N... ..O 6.6 .6.6 B. muaww cam mumop Eouw 838mm mo mw>uno cojumawmvnvmoq 2. 92%.; .EE eaten—600 0 V N o o .8 f... .- I a..%.::. .3 .3... I». Q \ \x \ x \ \ a \ \ .50 \ \ /l\ __ \ /\ 5. .EE .cotuoton N x \ Econ on On“ '5’! ‘9001 58 lower calcium diets. The weakness was probably a result of the decreased body size and femur weight caused by the elevated calcium. The bone composition and strength data reported in this trial differs with published work of Miller gt El! (1962), Zimmerman 33 El. (1963) and Rutledge 32 El- (1961) who reported increased bone calcium and strength with increasing dietary calcium. Some degree of turbinate atrophy was present in both sexes and on all dietary calcium treatments. The in- clusion of cartilage in the bony matrix was very conspicuous whenever the turbinates were atrophied. Figure 2 clearly depicts the extreme differences observed between the normal and abnormal turbinates. The sections of abnormal turbinates (B. D and E) are almost devoid of bony matrix and the inclu- sion of cartilage is very noticable. Normal mineralization was evident at the epiphyseal plate of the phalanx and no treatment or sex differences were observed. Increased dietary calcium did not prevent the occurance of turbinate atrophy as reported by Brown 23 El! (1966) and Pond gt El- (1966b). Simple correlation coefficients between and within bone. blood and performance parameters from experiment 1 are pre- sented in table 7. Fresh weight of the femur was significantly correlated with pig sex (0.u8) and average daily gain (0.39). Breaking strength was negatively correlated with dietary calcium level (-.39) and positively related to final serum Figure 2. 59 Photomicrographs of normal and atrophied turbinates: dorsal scroll, normal (A) and abnormal (B); lateral attachment, normal (C) and abnormal (D); ventral scroll, normal (E) and abnormal (F). 60 60.000.000.033 0023 3.0256 0.... vows 0.02» mmfim 3.0. :95 dawn 0 0.3 om.o 26% @023. 65 HohoH mm on» as 0.500%»: 0.3 mn.o o>ond “MN“wflmwowmvanvwfimwwwnmfinfl .0 00.0. 00.- 00.0 00.- 00.0 00.0 00.- 00.0 0H.- 00.0 00.- 00.0- .0\.u;onom 00.0 00.0 0H.- 00.- 00.- 00.0 00.- 00.0 00.- 00.0 00.- 0 0000 00.0 a0.- 00.0 00.- 00.- 00.0 00.0 00.- 00.0 00.- 00 0000 00.0 00.- 00.0 00.- 00.0 00.0 00.0 00.- 00.- 00000000 .00000 00.0 00.- 00.- 00.0 00.- 00.0 00.- 00.- 0000000 .00 00.0 00.0 00.0 00.0 00.0 00.- 00.0 000000.0000 00.0 00.0 00.0 00.0 00.- 00.0 0.00000 00.0 00.0 00.0 00.- 00.0 00_a0000 00.0 00.0 00.- 00.0 040 00.0 00.- 00.0 0000 0H000 00.0 00.0 0553.5. 00.0 000 a...“ 1 .0. .0. ”00 ”0. “a. .0 a a. ‘ .5 a anqaauogxuv ‘ . I . . . A mauve—3.0.20 0053.3.“th Ea 0000.3. .2020 and: v.5 082509 manodofimhmo o nodpuflohhoo .0 00000 61 calcium concentration (0.50). Dietary calcium level was negatively correlated with daily gain (-.24). final serum calcium concentration (-.32). final serum inorganic phosphorus concentration (-.31), femur weight (-.33), and femur specific gravity (-.35) but these coefficients were not statistically significant due to the small number of animals used to develop them. 2. EXperiment 2. Growth. feed consumption and feed utilization are summarized in table 8. Boars grew faster than the gilts for the 0-4 week and 4-8 week periods and for the entire experi- ment. Increased dietary calcium decreased average daily gain of both boars and gilts and the difference was most con- spicuous for the 0-4 week period. Neither increased dietary calcium nor sex exerted any influence on daily feed consump- tion or gain/feed ratio. The effects of sex and dietary cal- cium level on the pig performance agree with experiment 1 and the growth differences due to sex are greater in magnitude than in experiment 1. Bone composition. density. strength. and histology are presented in table 9. The gilts had significantly higher ash and calcium concentrations in the phalanx than boars (P < 0.01) and nearly significantly higher phosphorus concentration (P < 0.07). Estrogen administration has been shown to stimu- 62 .ndol on» no 00000 chaundvm H 00.0 .00.0-;;0000..-0000 0000.; 0040 00.0 .z0000\00¢0 00.0 00.0 00.0 00.0 00.0 00.0 00.0 .00 0000000003 0000 0000000 0000 00.0 00.0 00.0 00.0 00.0 00.0 00.0 00.0 00.0 .00 .0000.00000 00000 00.0 00.0 00.0 00.0 00.0 00.0 00.0 00.0 00.0 00.0 .00 .0000 00000 000: 0-0 00.0 0000 00.0 00.0 00.0 00.0 00.0 00.0 00.0 00.0 .00 .0000 00000 0000.0-0 00.0 0000 00.0 00.0 0.00 0.00 0.00 0.00 0.00 0.00 .00 .00000:.00000 00.0 00.0 00.0 00.0 0.00 0.00 0.00 0.00 0.00 0.00 .00 .00000: 0000000 .0. 0.0000000 0 .0 000%. 0 .3000 .0 0000000000 00 00000000000 000 00 0000000 .0 00000 .00.0 v .0 00 0000.0 v .00 0.000» .0050 0.00 0000 00000.00 0000000000000 0 .0_o.o V m 30 ”30.0 v 03 0000.00» 008.0 0003 8003 0300.00 00.350.00.23...” 00 .36 v m on 23.0 v .5 0000.300 3.003 00000..“ 00003 000.095 havfioaawdm o ,.00.0 v 0 an 2.00.0.0 v .00 00000» 25. 00000 00000 0300.00 0000000000000 .0 .00.0 v 0 00 200.0 v as 0000» 00000 0000 00000.00 0000000000000 0 .9350 u m 50.0.8605“ 00 50.03.00 u m 3003.00 bob u N 2.19300 n .0 N .0002: on... .00 00.0.00 00.0.0080me 00.0 ..00.0.-.00.0 00.0 00.0 00.0 00.0 00.0 00.0 00.0 000000000 0000000 00.0 00.0 00.0 00.0 00.0 00.0 00.0 00.0 00.0 00.0 000000000 000000000 00.0 00.0 00.0 00.0 00.0 00.0 00.0 00.0 00.0 00.0 0000000 000000000 M003 00.0 00.0 00.0 00.0 0.0 0.0 0.0 0.0 0.0 0.0 0 00.0 00.0 00.0 00.0 0.00 0.00 0.00 0.00 0.00 0.00 0o 00.0 00.0 00.0 00.0 0.00 0.00 0.00 0.00 0.00 0.00 000 0nnmmummwu0uuuumwaumummmumu 00.0 00.0 00.0 0.00 0000 000 0000 0000 0000 0000 .0on00 .000000 0000000 00.0 00.0 00.0 0000 0.00 0.00 0.00 0.00 0.000 0.000 .00 .00000000 00000000 00.0 00.0 00.0 00.0 00.0 00.0 00.0 00.0 00.0 00.0 0000000 00000000 00.0 00.0 00.0 00.0 00.00 00.00 00.00 00.00 00.00 00.00 .00 .00000: 00000 00300000 00.0 00.0 00.0 00.0 0.00 0.00 0.00 0.00 0.00 0.00 0 00.0 00.0 00.0 00.0 000.00 000.00 0.00 0.00 0.00 0.00 0o 00.0 00.0 00.0 00.0 00.00 00.00 00.00 0.00 0.00 0.00 000 «mumumuwuxuuuumwammuwumu 30.0.0. 00 Mom Rom 5.0.0. 0mm...” . R 500000.060. Ildflflflflflmul 000. .N 000050000008 00.0 00040me 00:00 0530.000 $000306 500000000003 00800 .00 gm .0 0.30.0. 64 late endosteal bone formation and has been used to treat senile osteoporosis in women, while neither testosterone nor pro- gesterone had any affect on bone formation (McLean and Urist. 1955). Thus, the sex differences in phalanx ash in eXperiment 2 and breaking stress in experiment 1 might be caused by estrogen secretion in the gilts. Calcium content of the phalanx was increased slightly by increased dietary calcium. These results do not agree with experiment 1 but the increase in bone ash and calcium due to increased dietary calcium is in agreement with the previously reported work of Miller gt al. (1962). The boars, as in experiment 1, had significantly heavier bones than the gilts (P < 0.01). Furthermore, the breaking strength and bending moment were higher for the boars than gilts. Increased dietary calcium caused bone weight and strength to decrease and the reduction was more severe in the boars. The load-deflection curves for experi- ment 2 are shown in figure 3. Bones from the boars were stronger than bones from the gilts. and increased dietary calcium had a greater detrimental influence on bone strength of boars than gilts. Bone density was not affected by either pig sex or dietary calcium level. Dietary calcium level exerted similar effects on the strength characteristics of the metacarpal in experiment 2 and the femur in experiment 1. These decreases in bone strength caused by high dietary 65 .AN .uaxmv aawoawo xumuoav N~.H no m.o .o.o vow uuaww paw mason Bonn mamaumomuma mo mm>u=o cowuooamovunooq .m muswwm .55 50:90:00 .55 fated—mun m c n N p O a Q n N _. ON .8 s3 .. ll .3 shall... .3 sod 3:0 66 calcium are not supported by the reports published in the literature. Composition of the turbinates was more variable than that of the phalanx and significant differences were more difficult to detect. The turbinates had lower ash, calcium and phosphorus concentrations and lower calcium to phosphorus ratios than the phalanx. Gilts had slightly higher turbinate ash concentration than the boars which parallels the sex difference observed in phalanx ash concentration. Increased dietary calcium tended to increase turbinate ash and decrease turbinate phosphorus but the differences were not significant. The composition of the turbinates did not prove to be superior to phalanx composition in estimating bone mineral status. Again. as in experiment 1. some turbinate atrophy was present in all lots. Increased dietary calcium did not alter the incidence of atrophy which differs from the reports of Brown gt 3;. (1966) and Pond gt filo (1966) but does support the findings of Libal gt 3;. (1969) who reported no efficacy of elevated dietary calcium in preventing turbinate atrOphy. Turbinate atrophy observed in these two experiments was not of pathogenic origin and inflammation was conspicuously abs sent. Again as in experiment 1, cartilage was noticably included in the bony matrix when atrOphy was observed. Normal mineralization was observed at the epiphyseal plate of the B. 6? phalanx and was not affected by pig sex or dietary calcium. Simple correlation coefficients between and within bone and performance parameters are presented in table 10. Be- tween bone and performance parameters, average daily gain was significantly correlated with bone weight (0.74). specific gravity (0.52). breaking strength (0.57) and turbinate calcium concentration (0.32). The correlation coefficients within bone parameters are interesting and the very low relationship between phalanx and turbinate composition was unexpected. Furthermore, the relationships between turbinate ash and turbinate mineral content were 2 to 4 times greater than the relationships between phalanx ash and phalanx mineral content. Expressing phalanx calcium and phosphorus as a percent of the bone ash did not improve the relationships between bone ash and bone mineral content nor the relationships between phalanx and turbinate composition. From these data one may conclude either that the composition of the phalanx is not an indicator of the composition of the turbinates or the variation in turbinate composition eliminated manifestation of any close relationship that might be present. Influence of Sex on the Zinc Requirement of Developing Swine. 1. Experiment 3. The performance and blood data from experiment 3 are 6E3 swam cud mm.o chops omen» .mpcofiOdmmooo omen» deflobop op coma ono3.mw«m as Scam spun N .Ho>.H as on» a. onooaoac fine Hopoa fin on» we anacondnmdm one mN.o shone mpnofioamwooo Gadpafiouhoo Had H 00.H 00.0 ma.u 0H.s 00.a mo.u o0.a 0H.o No.0 00.0 em.0 om.0 o0.s ms.a .mmnmouao .puao 00.H 0~.a mm.- 0o.a H0.- m0.u oo.a ma.0 no.0 om.0 0a.0 o0.0 No.0 annoy». .puso 00.” 00.0 no.0 0o.0 mo.a no.0 0H.0 HH.a no.0 no.0 oa.a no.0 monogamoom 00.o 0a.0 00.0 00.- 00.0 no.0 N0.a 0N.0 mm.0 No.0 0«.0 aaaooao 00.“ 0H.0 00.- mH.0 mm.o 00.0 0H.0 0N.0 oo.a 00.- gm. opooooaoo 0o.“ HN.0 50.0 00.- 0H.a mm.» 00.- 00.0 om.a monogamoom 00.6 Ho.0 “0.0 oa.o so.e o0.0 0N.o on.u sodoaoo 00.H “0.0 No.0 mm.a mo.a No.0 Ho.. 3.. weafiaom 00.6 so.o mm.o am.0 0H.» oH.0 someone. .aooum oo.a H:.o mm.o mo.n 30.: hvd>ahm .mm 00.o sa.0 Na.e 0s.0 somamz ozom 00.H No.a no.0 sham aaawn 00.o 00.0 somaoamto 00." xwm .puoo .auo4 m .0 om< m .0 om< .upm .po .y: oq< .ouo wow .omsa .guss .nuoa .wpuse .pneo .uom .wam .osm .anm .om onom N.mAN unmaduoafimv.mnmpoamhma concepomnoa use osoc.:a£po3 one coospon mnsofiOHmmooo moonwaonnou .oH canoe 69 presented in table 11. Pigs receiving the higher zinc levels (60 and 90 ppm) gained significantly faster than pigs re- ceiving the low zinc diets (P < 0.01) and this difference was evident as early as 4 weeks into the trial. The growth rate of the intact animals, boars and gilts. was more severely reo duced by inadequate dietary zinc and the sex x treatment interaction was significant for 4-8 week daily gain (P < 0.03). The total average daily gain of barrows was significantly greater than that of boars or gilts (P < 0.04) and the differ- ence was due to the superior growth rate of the barrows on the low zinc diets. Feed consumption and conversion to liveweight gain were improved by additional dietary zinc and the improve- ment was greater for boars and gilts than barrows. Further- more. boars consumed less feed than either barrows or gilts and were more efficient in utilizing this food for growth. On the low zinc diets. 57% of the boars and 43% of the gilts developed parakeratosis while none of the barrows showed any skin lesions; furthermore. the lesions of the boars were more severe than those of the gilts. Figures 4, 5 and 6 show the marked differences in the incidence and severity of the parakeratosis observed in experiment 3. One boar was very tolerant of low dietary zinc and gained normally throughout the experiment; however, figure 4 shows the marked growth reduction and skin lesions in the other boars on the low 7O .Ho.o.v m mm unmo.o v_mv hogan» smbom umwmfl comp hopnothhaecoommfiswmm w . .wo.o_v_m no ”Amo.o.v_mv mosHmb Kmm Momma can» movooam oHpsmenmmswmm m .H0.0_v o oo ”Am0.0 v my moon.» ooao ooooa noon oooooon naooooannoono o .Ho.o_v m.pp ”Ano.o_v my mosfior poem momma swap «museum thswommnsmnm p .oo.0_v o oo nAmogov n0 moon.» ooooo nooofi coo» oooooon naooooonnonam o .80 v o no xm0.0 v & moon.» .50 no.3 5o... pooooon fipfionhonnm n °no.0 v o 2. ”30.0 v no .32. to: goo... oooooon nnofionhonao o - _ .sooa on» mo henna phouaopm H no.0 no.0 00.0 oonm on noon oom .0n oomm oono on Hogan nm.0 no.0 00.0 oomm on non oomm nn onnn ooom on onooz n 0000 0N00 00.0 000% HN MH®® 00mm #N wam 00mm wN mxoosp 4w no.0 on.0 nn.0 no no mn om no om on no HoaonoH .HE oon\moa .ondu ashom no.0 no.0 00.0 H.n n.o nn.n om.n no.n oon.n oon.n o.o Hoonn no.0 no.0 00.0 n.n oon.o nn.n ooo.n ooo.o no.n oo0.n o.o onooa n nn.0 no.0 00.0 on.“ n.0 oonto. eon.n n.o oon.n ooo.n oom.o onoo: o no.0 mo.0 nn.0 0.0 m.n n.n n.n 0.: n.n n.o n.o HooonoH muons wawmm .omouonamonn oqaamxfld sshom n\0 n\n n\o n\0 n\o n\0 nno nno an no ooooonooH mn.0 nn.0 no.0 nn.0 on.0 nn.0 on.o nn.0 0n.o nn.0 nn.0 on.0 oooo\oaoo nn.0 no.0 mn.o oon.n o0n.n 0m.H nom.n oon.n no.n oo.n oon.n mm.n .na .ooon nanoo .oon no.0 no.0 00.0 no.0 con.o oonmo no.0 omn.0 oon.0 oinnmo onn.o eon.o ono.o .oaon nanoo Hoooo no.0 om.0 00.0 no.0 oon.0 onom.0 nn.0 noom.o o0n.0 nonm.0 oonm.0 nnn.0 nn.0 .na .oq< noon was nm.0 nn.0 00.0 oonm.0 nn.0 oonm.0 oonm.0 oo.0 ooom.0 ons.0 ono.o .na .ono goo: :00 nn.0 no.0 00.0 nn.n on.no nn0.mn o.nm oon.no oon.no poo.0n oon.oo oo0.no m.om .nn .oonnos Hogan 00.0 no.0 no.0 nn.0 m.on n.oo m.oo n.0o 0.mo m.oo n.0n n.oo n.oo .oa .oonnos HonoonH .ooo x now now .ooo 00 on 0o on on 0o 0o 0n goo .ocoEooooo o.on OOQwOHMfiQMflm mwflfim 9.5.»th mhwmm Nam .m unmanaoawo so mnmnHmsm pooHn use oeswshownoa wnm.mo humssom .wn oHflne 71 Figure 4. Boars fed a diet containing less than 30 ppm of zinc (Expt. 3). Figure 5. Barrows fed a diet containing less than 30 ppm of zinc (Expt. 3). Figure 6. Gilts fed a diet containing less than 30 ppm of zinc (Expt. 3). 72 zinc diet. Figure 5 shows the greater uniformity in size of the barrows and freedom from parakeratosis when compared to either boars or gilts, figures 4 and 6, respectively. Serum alkaline phosphatase activity was significantly reduced by inadequate dietary zinc at all bleeding periods (P < 0.01). At the 8 week and terminal sampling periods, serum alkaline phosphatase activity of the boars and gilts on the low zinc diet was significantly less than that of the barrows (P < 0.05). In addition. the maximum enzyme activity was observed on the high zinc diets in all sexes. Serum zinc concentrations were significantly reduced by lowered dietary zinc (P < 0.01), but differences between the sexes on the low zinc diet were small and non-significant. 0n the 60 ppm diet the serum zinc concentration of the barrows was higher at the final bleeding than boars or gilts and the difference was significant (P < 0.05). Both serum zinc concentration and alkaline phosphatase activity were sensitive indicators of dietary zinc levels. Many workers including Luecke gt 3;. (1956. 1957). Hoekstra 91; 9;. (1956). Hoefer gt 5;. (1960). Ritchie gt 2&0 (1963), Shanklin 23 El! (1968) and Miller gt El- (1963b)have reported similar effects of dietary zinc supplementation on growth, feed consumption, feed efficiency. serum alkaline phosphatase activity and zinc concentration to those observed in this experiment. However. only small 73 differences in growth, skin condition and blood data between boars and gilts on the low zinc diet were observed which differs with the findings in the baby pig of Miller 2E.El° (1969). Upon termination of the experiment, one severely para~ keratotic boar was examined histopathologically and was found to have a moderate parakeratosis of the esophageal epithelium in addition to parakeratosis of the epidermis. Furthermore, the testes were aspermatogenic and the seminiferous tubules contained only spermatogonia while no spermatids were ob- served in the tubules. Luecke gt 2;. (1968) had previously reported parakeratosis of the eSOphagus and aspermatogenesis in the testes of the zinc-deficient male rat. In summary, pig performance, incidence of parakeratosis and serum alkaline phosphatase activity of boars, barrows and gilts fed three levels of dietary zinc indicate that boars and gilts both have a higher zinc requirement than littermate barrows. Serum zinc concentration was a sensitive measure of dietary zinc level but differences in serum zinc between the sexes were minimal and inconclusive. 2. Experiment 4. The results of experiment 4 are summarized in table 12. The effect of low dietary zinc on pig growth and incidence of 74 .mo.0.v o no uAmo.0_v n0 moon.» ooooo on. goon oopooon nHoqooHoaonnm o .Ho.o v m mm ”Amo.o_v my mosfinb coeom paced mono hoveohm thzwonmnswnm w .Ho.0_v a on nAm0.0.v o0 oooHo>_xoo pooon coop oooooon monsoonoaonam n .Ho.0_v o oo uAmo.o_v o0 moon.» ooom pooon coop oooooon noooooaoaonam o .00.0.v o 00 ”Amo.0_v o0 ooooop noon oooon coon oooooon nHoooonnnonao 0 .00.0 v o oo MAmo.0_v n0 moon.» ooooo swoon goon oopooon naooooooaonno o .Ho.o.v A pp “Amo.o v my mosflo> cap women can» uopoouw hHusoonmdcwmm n .no.o_v o oo ”Am0.0_v no can.» ooooH coop oooooon nooooonoaonnm o .sdoa on» no gonna caducopm H no.0 mo.0 00.0 no.n ,ooom ooom on snow oomm 0n 0:0 ooo0 on Hogan nn.0 00.0 00.0 nn.n 00n0 oomm an man 00:0 000: 0000 oon0 0n 0n.0: n n0.0 00.0 00.0 nn.n nnn0 oooo o0n 0000 oom: mn oom oooo on onoo: o no.0 00.0 nm.0 on.n on0 noon oom ooo0 om o0m oo nm o0m HonoooH .Hs oon\moa .osan sshom 00.0 no.0 00.0 00.0 0.n n.n 0.n n.n n.n 0.n 0.n nno.n 0.n Hogan no.0 nn.0 00.0 2.0 ”wan omen n.n Mann ”men 00...... ”wan fem o; 3.20 00.0 00.0 00.0 0n.0 oo0.n ooo.n 0.n oon.o oon.n 0.0 on.: 00.: n.« 0n.03 o m0.o 00.0 00.0 00.0 non.m nno.m ooo.n non.o n.n non.o ooo.n m.n mnn.o Hangman muons msmmm omwponmmonm ocdfiwxau aspen 0\0 0\0 0\o 0\0 0\0 0\0 0\0 0n0 0\H no no oooooaooH no.0 no.0 00.0 nn.0 nn.0 0n.0 0n.0 nn.0 0n.0 0n.0 nn.0 0n.0 oooo\onoo no.0 o0.0 oo.0 nn.n on.n oo.m 0m.n nn.n no.n nn.n on.n on.n .0: .0000 nnaoo .oo< 00.0 no.0 no.0 no.0 pon0.0 o00.0.0 0m.0 n00.0 non0.0 0500 000.0 ppn0.0 0m.0 .nn .onon naooo H.009 nn.0 m0.0 nn.0 no.0 o0.0 00.0 00.0 ooon.0 0mn.0 nno.0 o0n.0 onc.0 n0.0 .nn .094 no.2 on: 00.0 00.0 0n.0 no.0 mm.0 nm.0 mm.0 om.0 nm.o 00.0 nn.0 nm.0 om.0 .nn .004 now: 0.0 00.0 on.0 0n.0 on.n m.no H.0o 0.00 n.oo n.no n.0o n.no n.no m.nn .nx .oonnoz Hogan on.o oo.0 0m.0 0n.0 0.mo n.00 0.00 n.0m o.mo n.0a n.mn n.0o n.0o .nx .oooao: HononoH mmmmumummm oom .ooo snow on om on on 0m on on 0m on goo .oooEPoooo oonn OOCwOfiMHCMfim mpflfio mBOhhwm mhmom Kmm .: pcosfinooxo Econ mnmhfimsm pecan can manoeuomnoa mom mo hhnesdm .mn macaw 75 parakeratosis was not as dramatic as in the previous experiment. The slightly higher initial weight and the higher zinc content of the basal diet in experiment 4 probably are the reasons for this variance. The 4-8 week daily gain of the barrows was significantly greater than the gain of either boars or gilts (P < 0.05); moreover. the growth rate of the boars and gilts was depressed on the low zinc diet while the growth rate of the barrows was not altered. Boars and barrows on high zinc diets had similar growth rates which were superior to the growth rate of the gilts. The daily feed intake of the boars and gilts was slightly decreased by inadequate zinc while in- take of the barrows was not altered. In addition. the boars consumed less feed than barrows or gilts and were slightly more efficient in converting food to liveweight gain. The feed efficiency of the boars was slightly depressed by inade- quate dietary zinc. but this was not observed in the barrows or gilts. The incidence and severity of parakeratosis was much lower in experiment 4 than experiment 3. but it appeared in the same lots. No parakeratosis was observed in the barrows on low zinc while 12.5% of the boars and 12.5% of the gilts showed some degree of parakeratosis. Initially, the serum alkaline phosphatase activity of the gilts was significantly higher than that of the boars or barrows (P < 0.01) which was at variance with the reported 76 observations of Tanabe and Wilcox (1960) that male chicks had higher serum alkaline phosphatase activities than female chicks but agreed with the results of experiment 1. At all subsequent bleeding periods supplemental dietary zinc signifi~ cantly increased alkaline phosphatase activity (P < 0.01). A significant sex x treatment interaction existed at the 8 week bleeding since the boars on low zinc (30 ppm) had the lowest activity value (1.9) while the boars on 50 ppm dietary zinc had the highest activity (5.2). The extremely high activity values for the boars on 50 ppm dietary zinc at 4 and 8 weeks are difficult to explain and are probably due to chance variation. Both boars and gilts on the low zinc diets had lower alkaline phosphatase activities at the 8 week and final bleeding periods than the barrows and the difference was signi- ficant for the final bleeding (P < 0.01). Initial serum zinc concentrations paralleled alkaline phosphatase activity and the gilts had significantly higher initial serum zinc con- centrations than barrows or boars (P < 0.01). Significant reductions in serum zinc concentrations were observed on the low zinc lots for all subsequent bleedings (P < 0.01). Barrows had significantly higher serum zinc at 8 weeks than boars or gilts (P < 0.04), and the zinc concentration of the barrows on the high zinc diet was higher than all other treat- ments at the final bleeding creating a significant sex x 77 treatment interaction (P < 0.02). The differences in serum zinc concentration between the sexes on the low zinc diet were minimal; however, boars had slightly lower concentrations than barrows or gilts. The results from experiment 4 support the observations of experiment 3 and support the conclusion that both gilts and boars have a higher zinc requirement than barrows. This sex x zinc requirement interaction is probably related to the hormone levels; however. active gonadotrophin secretion from the pituitary, which Gunn gt al. (1960a,b, 1961) has shown to influence zinc uptake by certain tissues, would be minimal until near the end of the experiment and long after the differences have been observed. Theuer andHoekstra (1966) have reported that zinc deficiency in the rat interferes with normal protein metabolism but does not alter fat or carbohya drate metabolism. If Theuer and Hoekstra°s findings are also true for the pig, then boars and gilts could have a higher zinc requirement than barrows due to higher synthesis of lean tissue. Also. boars have more bone. which contains considerable zinc, than barrows or gilts. Thus. more dietary zinc is rem quired to maintain the larger body zinc stores of boars and gilts. 3. Experiment 5. Pig performance and blood analyses from experiment 5 78 are summarized in table 13. The animals used in this experiment were approximately 1 week younger and 1~3 kilograms lighter than the animals in the previous experiments. The low zinc diet caused a significant reduction in the 0~8 week and total average daily gain of the barrows and gilts (P < 0.01), but only caused a slight reduction in gain of the boars. Daily feed intake was reduced to a greater extent in barrows and gilts fed the low zinc diet than boars. Inadequate dietary zinc caused a slight reduction in the gain/feed ratios of the barrows and gilts but not the boars. The incidence of para- keratosis was greatest in the barrows fed the low zinc diets with 37.5% of them showing skin lesions. Twenty-five percent of the gilts and 12.5% of the boars on the low zinc diets be- came parakeratotic. Comparative growth and skin condition of the sexes in this experiment disagree with the observations in the previous two experiments and are difficult to explain; however, some problems were encountered in this experiment that might have influenced the results. At approximately the eighth week of the experiment one pig died suddenly and the cause of death was diagnosed as vitamin E deficiency. Vitamin E was then added to all rations at this time and the growth rate and general appearance of all pigs improved markedly. Another problem was that the low zinc boars shared a common automatic waterer with the high zinc gilts. Upon 79 .no.o.v m we ”Amo.o_v my mosdea heave fine soap nopoohm hapsoonmmswnm o .00.0 v o 00 W“m0.0 v.m0 ooonop ooom oooofi soap oooooon nnoooonnaonnm o .00.0 v o oo .Am0.0 vane moon.» coon» oooon noes oooooon nHooooaoaonnm o .oo.o.v n n .Amo.o_v m0 moon.» on» oooon coo» oooooon naoooonnaonnm n .n0.0mv o oo .Am0.o v n0 00H.» oooon zoo» oooooon naoqooannonoo o . .cnos on» we gonna pneucepm H nn.0 00.0 00.0 no.n oo00 nn oom0 _0n ooon .nn Hogan m0.0 0n.0 00.0 m0.n oonm nn oo00 0n oonm 0n on.0: n nn.0 00.0 00.0 mo.n oo00 mn oon0 nn .000 one on.0: o m0.0 o0.o on.0 om.o ooon 00 00 oonn 0n o0 HonoeoH .HB 00n\mos .osda aspen no.0 0n.0 00.0 m0.0 on.n n.n on.n oon.n ooH.n n.n Honda mo.o 0n.0 00.0 00.0 oo0.o 0.n oon.n 0.n oon.o 0.n on.0: n oo.0 no.0 00.0 nn.0 oo0.o n.n oon.o n.n oon.o ono.n onooz o nn.0 m0.0 mo.o on.0 n.0 n.0 0.n n.n 0.n n.n HonoaoH nuns: sawdm .omepwnmmonm osddwxfiu sshom n\0 n\n 0\0 0\n nno n\o no no ooooonooH mn.0 0n.0 no.0 nn.0 on.0 on.0 0n.0 0n.0 nn.0 oooonoooo m0.0 00.0 00.0 mo.o o0.o on.n 0m.o no.n on.0 .na .0000 nanoo .000 m0.0 00.0 00.0 no.0 ppn0.0 oo.0 pnn0.0 m0.0 onn.0.0 nonm.0 .nx .oaon nanoo H.009 o0.0 on.0 00.0 no.0 anom.0 no.0 o0m.o 0n.0 nonm.0 ooom.o .nn .enon mason .n: 0.0 nn.0 on.0 no.0 on.n poo.on m.m0 n 0.00 0.n0 o00.o0 non.on .nn .oonaoa Hogan oo.0 nn.0 nn.0 0n.0 o.no n.na .nH o.nn n.no 0.nn .na .oonaos.flonoaoH .ooo x woo woo .ooo new”. on - on on on -0n on .ooo .ocoeooooo oonn liilMMflMMflMMflMMMEJIII mpflwo meonhem modem flow .m.»sosmuoaxe Seam.mnmmanw pecan.psw.eecwswowamm moo Ho.mumss:m omn-odama 80 analysis, the zinc concentration of the water consumed by the low zinc barrows and gilts contained 16 meg/100 ml., the low zinc boars and high zinc gilts contained 39 meg/100 ml., and the high zinc barrows and boars contained 46 meg/100 ml., with feed contamination being the major source of zinc in the water. Thus, the boars on the low zinc diet were consuming over twice as much zinc in their water as the barrows and gilts on the low zinc diets. The differential response of the barrows to low zinc diets in experiment 5 and experiments 3 and 4, may be related to the length of time between castration and the beginning of the experiment. Pories and Strain (1966) have shown that zinc concentrates at the site of a wound and is instrumental in rapid wound healing. Perhaps castration causes the con- centration of zinc at the wound site and increases the body storage of zinc in the barrows when they are consuming a high zinc diet prior to initiation of the experiment. In experi» ments 3 and 4, the time between castration and the initiation of the experiment was 7 to 10 days longer than in experiment 5 and may have been sufficient for adequate zinc storage to take place and thus prevent parakeratosis in the critical, early part of the experiment. Furthermore, the vitamin E deficiency in experiment 5 may have caused enough additional stress on the barrows to precipitate parakeratosis. 81 Initial serum alkaline phosphatase activity was lowest in the gilts which contrasts with the observations of ex~ periments 1 and 4. At 4 weeks boars had significantly higher serum alkaline phosphatase activity than barrows and gilts on the corresponding zinc level (P < 0.02) which caused the sex x treatment interaction to be significant at the 0.04% level. Inadequate dietary zinc caused a significant depression in serum alkaline phosphatase activity in all sexes at all bleeding periods (P < 0.01). At 8 weeks no significant differences in activity between the sexes on equivalent zinc levels were observed; however, at the final bleeding serum alkaline phosphatase activity in the bears on the low zinc diet was significantly less than that of the low zinc barrows (P < 0.01). The difference in enzyme activity between the barrows and gilts on the low zinc diet approached significance. In addition the gilts on the high zinc diet had the highest enzyme activity at the final bleeding which caused a signifia cant sex x treatment interaction (P < 0.01). Increased dietary zinc levels significantly improved serum zinc oonm centration at all bleeding periods (P < 0.01). At 4 weeks the serum zinc concentration of the boars was significantly greater than that of the barrows and gilts on corresponding dietary zinc levels (P < 0.05), while the zinc concentrations of the barrows and gilts were not different. At 8 weeks and 82 the final bleeding serum zinc was not significantly different between the sexes on equivalent zinc levels; however, the low zinc boars had the lowest serum zinc concentration at the final bleeding. The serum analyses, especially for the 8 week and final bleeding periods, support the results of experiments 3 and 4 in spite of the pig performance results in this experiment. 4. Correlation Coefficients. Correlation coefficients between and within blood and performance parameters are presented in table 14. Data from 183 pigs from experiments 3, 4 and 5 were used to develop these coefficients. Within performance parameters 0-4 week average daily gain was significantly correlated with total daily gain (0.36) but not with 4m8 week daily gain (0.10) which was highly correlated with total daily gain (0.71). Between performance and blood parameters 4~8 week and total daily gain were sigo nificantly related to 4 and 8 week and final serum alkaline phosphatase and zinc values and gain was more closely re» lated to serum zinc than to serum alkaline phosphatase. Initial and final alkaline phosphatase activities and initial serum Zinc concentrations were negatively correlated with 004 week average daily gain. Within blood parameters serum alkao line phosphatase activity and serum zinc concentration were 83 .mpCmnowmmeoe omen» monsoon on come one? mwna mmw scam oven N .woaofl fin on» no psoonmacmno can ow.o obepn omega can Hobofl an on» an panefimnsmnm one nn.0 macaw masenefimmooe conveaoupoo HH< n 00.0 n0.0 nm.0 0n.0 no.0 om.0 on.0 00.. -no.0 on.0 no.0 o0.o .-n0.o on.nooan 00.0 n0.0 no.0 mn.0 nm.0 00.0 no.9 om.0 nn.0 0n.0 mn.0 no.0 on .n: n 00.o on.0 on.0 no.0 00.0 no.0 om.0 nn.0 00.0 0n.0 m0.0 on .n3 o 00.o 00.0 «0.0 00.0 0n.0 00.0 00.3 nn.n 00.0 00.0 on .pneH 00.0 nm.0 nm.0 mn.o on.0 on.0 nn.a 0n.0 no.n n40 Hogan 00.o om.0 o0.o nn.0 0n.0 no.3 om.0 no.0 mom .x: 0 00.0 0n.0 nn.0 mn.0 o0.a no.0 0n.0 ooH coax» mom mpaww tam mason Scum hpnmsop paw npwccapm .mafio mason .e .32. smegma. 115 .Hahosow u o ”Hagen 1926 n 9 3.353 n n 3993603 u n ”2min” u N 33min» be» u a ”dunno: n o H ”vacanovaa opafivoahopcfi u H ”HHouom adhunob u > « o .ufi mm.fifi am.m~ om.n ‘om.ofi mfi.ua .m nfiumn a 0 ca mfiwfifi umwmm wfi.n m~.m noon“ a mama o 9H: as: ma.ofi mo.o~ o:.m mu.m ofi.nfi a «flush o o m>fi mayo“ mfi.m~ mm.m mfiomfi mm.o~ h mama H o o ao.ofi mn.m~ ma.: Nfi.m am.mfl x. mnfi a nu: n>¢ Ho.HH mm.o~ om.0 o:.HH mm.mfl .: m-mn o a a: 8.: 8.3 m3. 8:9 2.8 a a: c an om on.0“ nn.m~ nn.0 anxmfi amofim a m-nm asaofiao “a.“ o >H o mo.HH «m.mm nn.n «mood mn.mfi m anew o o o nn.0H nwomm mm.o «m.mfi meow“ a ofinun o 0 mm m~.HH ou.em 03.: mm.n Nfi.mfi a canon o o o mm.ofi on.m~ nn.0 afiomfi «m.mfi m anon o aHN um mm.fifi am.m~ nn.n mfi.ma om.~m : “finfi o am am nfi.fifi om.0m mmdo aaofifi “m.n“ Us «non o o o nn.0“ zo.w~ mm.“ HQONH venom z mafi o o pm no.fid mn.m~ an.m am.fifi mmomfi z anon asaofiao um.o o o o ma.o~ :o.m~ :m.w mfiomfi Enema m mama o o o om.0H Ho.mm :¢.m wmoofl amend a oasom o o o o:.HH mm.m~ mo.o m#°mfi m:.o~ m n-nm o o >m am.fifi No.0w mace no.fifi no.n“ m Hanna o o um om.o« mm.:~ am.u mm.mfi Hmomw z mo5m o >H a>m mm.o« mm.m~ m¢.m saga omofim : Own“ 0 o o um.OH on.nm ooom ooom“ up.fi~ : “sum 0 o o no.0“ Haonm no.n mm.mfi magmm xv moon asaofiao no.0 opmflm Gama opnmm agno~p< mama menu .2» cam 02m xwm ooz «mmOHopmam cease um mac .gm4 .mnmm .gmoum wfim aha .mxmv Bfifiofimo Mo mHmPoH oohxp com mpflaw flaw whafln Eoyw thHopmfix ovwnanhdv mfim.£owpwmnafioo Hmmhwwmpmz om mflpma xfiwammg< 8 wka 12 wk. 006% Calcium a WHO Serum calcium and phOSphorus concentrations in boars and gilts fed three levels of calcium (Expo 1)o Serum Calciuml mg£[100 ml Inito Sex Appendix Table 60 Pig Noo SC!)\OU\H\O(\ (\OMNHB o o o o o o o BBBBQNQ N\CO—d’«="<'\(\°-=);U\ OO\O\(‘:OO\O\O\ dot-*wNCDATN oooooooo HNNéMOMN HHHHHHHH QQDCDNNWGO oooooooo OOOHHHChq-G HHHHHH H xxxxmmmm H o MHONHb-Haa 08H I B an \0(\8(\\O(\\OC\ MMHmmmmm 0.9% Calcium 116 NO‘NG) N attainmvut. 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Pig Height. lben Histolo 1 N00 Init. h wko 8 wk. Fin. Turb.Atr0phy Cart. Ep1.Plate Int 32, Gilts hw9 #3 78 125 200 O 0 O 8m8 33 60 96 183 O 0 0 15a? 32 57 98 174 0 1D 0 20-6 37 68 116 207 16 0 0 35=9 43 86 132 20h O 0 1 56m11 44 83 132 257 BVD 3VD 0 56m15 #0 79 118 211 2G BIV 1 62u9 35 67 103 183 O 0 0 Average daily feed 5.22 lbs. Gain/feed 0°27 Total pig days 94h Lot 32A, Boars 891 37 74 115 208 2V 1VD 1 9w3 35 72 122 227 1G 0 1 93% £4 89 139 215 1G 0 1 10e1 35 ?6 131 234 16 1D 0 27a5 NO ?9 126 209 O O 1 29:1 36 T1 120 216 1G 0 O 33n3 39 75 116 208 16 2D 1 302:1 #3 87 1#3 2&3 a a 0 Average daily feed 5.27 lbs. Gain/feed 0°29 Total pig days 9hfl 1 “ 0 = normal; 1 = very slight; 2 = slight: 3 = moderate; h a severe D = dorsal scroll; V a ventral scroll; I = intermediate attachment; G E generalo '119 Appendix Table 90 Pig performance and turbinate histology of bears and gilts fed 0.99% dietary calcium (Ebtp. 2)° Pig W'eightleso Histolo Noo lnito 3 wk. 8 wko FEE?’ Turboltrophy ar 0 o a ZOmh 3% 67 113 205 1G 0 1 27a8 29 59 93 169 3VG “ID 1 3329 no 80 125 222 1G 0 O 3523 #2 82 131 218 0 1V 0 35m? #8 93 1h? 252 0 0 0 56m1& 33 67 106 199 2G 0 0 62m10 40 67 107 189 30 ED 0 62m11 36 69 115 180 3VD 3D 0 Average daily feed 5005 lbso Gain/feed 0.28 Total pig days 944 lot 33A, Bears 8m3 hi 75 115 205 O 0 1 9e6 #0 83 136 229 1G 0 1 925 37 69 113 206 0 O O 2021 27 53 93 18h 0 O 0 3382 #4 86 139 190 hVD “G 0 35ml 37 7b 120 224 “VD RG 0 30223 37 7 128 205 1G 0 O 2922 b? 82 135 2h? 0 0 0 Average daily feed 5031 lbso 3322 killed in gutter cleaner at Gainffeed 0.29 103 days (2/22/68) Total pig days 92.9 . 0 2 normal; 1 E very slight: 2 = slight; 3 2 moderate: h a severe D % dorsal scroll: V E ventral sorollg I 2 intermediate attachment; G a generalo 1 120 Appendix Table 10. Pig performance and turbinate histology of bears and gilts fed 102$ dietary calcium (EXp. 2)° Pig Eggght. lbs, fi Higtglogzj‘ H Noo Inito wk; wk; Fino TurboAtrOphy Carto ioPlate Lot 3%, Gilts 15:29 35 59 92 159 o o 1 20©5 33 61 100 182 “VD #6 0 20m? 36 67 110 205 16 1V 1 29ah an 79 123 213 0 0 0 35mh an 86 138 2&7 0 O O 56m13 43 76 129 235 1G 1V 0 56w16 3h 67 112 223 - - - 62-8 37 73 108 188 0 O 0 Average daily feed 5028 lbs. Gain/feed 0027 Total pig days 994 Lot 34A. Bears 8wh 37 6% 103 183 1D 2D 1 8m5 33 62 99 183 1G 0 2 921 43 7 130 222 a - - 1523 an 7 115 185 10 0 0 2723 43 80 12h 231 1G 1D 0 35oz h2 73 122 220 3G 0 1 302:2 3'? 74 112 198 2G 0 1 3022h 90 76 122 220 0 O 1 Average daily feed 5008 lbso Gain/feed 0028 Total pig days 9414 i O = normal; 1 3 very slight; 2 = slight; 3 a moderate; h a severe D E dorsal scroll; V a ventral scroll; I 2 intermediate attachment; G a general° 121 -.om no.n: nae. we.“ nm.e m.: we.“ on.“ m.: mad om.ea ma.ss we.m nm.0 5H.m wH.H n-nm mm.a~ n~.ae new. as. on.n m.e se.a mm.a m.e sea No.0“ mm.se on.n em.e H~.o« cm.“ “.0“ mN.HN “m.mm mom. HH.~ ma.o m.n as.“ on.H m.n ow sm.ma mm.ss sm.m as.“ 00.5 mH.H H-mm oa.- no.n: one. 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