V CflfiF‘éRESON 6F MGM? AND CHROME OXIDE £3 EEFERERCE EEYEEEALS EN {BE FLUX WHERE 9F NHTHEENT‘S THRGE’J‘GH TEE DIFFERERT SEC’HONS OF THE GASTMMTESE‘EML T3528? 823 SEER? “Nests EOP flu Deg?“ cg M. 5. ’ ECHEGKK 3%?5 EREYERSETY Karingattil Sam Varghese W70 -___ "'4" LIBRAR Y 4"” a Michigan State ? U niversity l t mm: mm“..- 1—1-52!“ IHESVQ h.— "4‘: LIBRARY L” :2 Michigan State Inesyg 3‘ University J. .. 943.: 3"me .c—c-mc and ABSTRACT COMPARISON OF LIGNIN AND CHROMIC OXIDE AS REFERENCE MATERIALS IN THE FLUX PATTERN OF NUTRIENTS THROUGH THE DIFFERENT SECTIONS OF THE GASTROINTESTINAL TRACT OF SHEEP BY Karingattil Sam Varghese Different kinds of markers have been used as reference materials in various studies. The use of markers are fairly common in investigation of digestibility coefficients, rate of passage, retention time, voluntary intake etc. In recent years markers have been used as reference materials of nutrients from the different sections of the gastrointestinal (G.I.) tract. However, few inVestigations have been performed in this area and the validity of the use of indicators should be further evaluated with more research in order to substantiate its use in such studies. Lignin has been used as a nonabsorbable marker in this study to measure the indigestibility as well as the flux pattern of seven different nutrients (dry matter, acid detergent fiber, magnesium, potassium, sodium, calcium and zinc) from nine different sections of the G.I. tract of 16 sheep. Four different hays were used as rations. The mineral determina- tions, and the flux of these minerals by the chromic oxide method were determined in a previous M.S. study. Karingattil Sam Varghese Lignin determinations for all the samples of the . ingesta and the forages were done according to the method of Van Soest. The indigestibility of the different nutrients was determined by the lignin ratio technique. Also the flux patterns with this indicator were measured for all the dif— ferent sections of the G.I. tract. The indigestibility of dry matter (D.M.) for the entire tract avaraged 3%%. Analysis of variance indicated there was statistical differ— ence in the indigestibility of‘dry matter among the sections of the gastrointestinal tract (P< 0.0005). The D.M. indigestibility in the rumen was 48%, indicating 52% absorp- tion from the rumen. In the upper small intestine an endogenous secretion was observed, but absorption and/or reabsorption occurred in the middle 5.1. and the lower sections of the G.I. tract. About 48% indigestibility was observed for acid deter- gent fiber (ADF) for the entire tract and rumenal disappear- ance of this nutrient amounted to 42%. The indigestibility of the minerals demonstrated a difference for the different sections (P<: 0.0005). For certain minerals the indigestibility indicated a significant difference due to forage (grass vs legume). In general, the 6 hour and 12 hour postprandial did not show much differences in indigestibility for the flux pattern of different nutrients. Karingattil Sam Varghese The flux pattern of minerals also indicated significant variation among the organs (P‘<.0.0005). An apparent absorption of Mg and K were observed from the rumen. For Na, Ca, and Zn the ruminal values were considered as the base values because of unmeasured dietary intake. A high endo- genous secretion was common for all minerals in the upper 8.1. In general, absorption occurred in the middle 8.1. and in the following further sections of the G.I. tract. Chromic oxide and lignin Were compared as indicators by measuring their ratio values. ‘The chromium lignin ratio indi— cated a highly significant difference (PIts Digestion, Absorption, and Secretion in the Gastrointestinal Tract Dry matter (D.M.) includes everything except water. Van Soest (1965) has divided forage dry matter on a nutri- tive basis into cellular and cell wall portions. According to him the cellular contents included lipids, most of the proteins, soluble carbohydrates, and most of the water soluble materials. The cell wall portion includes cellulose, hemicellulose and lignin that are insoluble in detergent solutions. Once the food is ingested into the mouth it passes to the rumen. A large quantity of saliva is secreted which is later thoroughly mixed with the stored materials in the rumen. Fermentation of the fibrous portion of the roughage occurs in the rumen, some carbohydrates undergo digestion, and some end products are absorbed from the epithelial layers of the rumen. The residues of the fermented portion together with the portion of the digesta which escaped digestion in the rumen move to other portions of the G.I. tract Where they are acted on by different enzymes in different sections and may be thus digested and absorbed. Secretion of some of these absorbed materials and reabsorption of the nutrients occur in the different sections of the G.I. tract. Rogerson (1958) thus described ”Digestion is in every sense a dynamic process, many actions and reactions occurring simultan— eously. Thus there may be food intake, food passage, 24 nutrient absorption, fermentation secretion, and synthesis, all going side by side in the same organ". Different types of carbohydrates have been studied to determine their digestibility and utilization. Philipson _§H§l. (1942) studied the digestion pattern of different types of carbohydrates in the rumen of sheep. They observed that glucose, fructose, and cane-sugar underwent rapid fermentation while maltose,'lactose and galactose were fermented less rapidly. Bondi and Meyer (1943) studied the chemical nature and digestibility of roughages and observed that digestibility ranged from 64.0% to 66.2% for soluble pentosans and from 74.0% to 76.5% for the insoluble hexosans. Weller g£_al. (1954) Studied the passage rate of starch through the omasum of the sheep. He showed that destruction of starch occurred in rumen as well as the omasum. The extent of digestion in the reticulo-rumen of cows was studied by Balch in 1957. The animals received 58% of the dry matter from the nitrogen free extract (NFE) frac- tion, 20% from the crude fiber fraction and total carbo- hydrates constituted about 80% of the intake. The result of this study suggested that on the average almost half (43%) of the dietary dry matter was digested in the reticulo- rumen and that some 80% of the apparently digested dry matter was in the form of NFE, and 13%.was crude fiber representing 81 and 54% of the total digestion of these fractions. In these studies the portion of dry matter 25 digested in the reticulo-rumen was much higher with diets high in concentrates than with those containing mainly or entirely roughage. For a roughage ration, the apparent digestion of crude protein in the reticulo-rumen was low, thus little or no absorption of nitrogen occurred from the reticulo—rumen. A range of 12 to 54% of dietary nitrogen disappeared from the rumen with high concentra- tions. The range of apparent ruminal digestibility of dry matter was 26 to 62% and the apparent digestibility of dry matter of the hind gut was 12 to 34%. Rogerson (1958) studied the digestion of different kinds of rations along the’G.I. tract of sheep. He used Rhode grass hay, Rhode grass hay plus Cassava meal, and Maize-meal as rations in three different groups. He db— served that 40%.of the dietary dry matter was digested in the sheep rumen on the hay diet, 50% on the mixed diet and 75% on the concentrate diet. In a total digeStibility study conducted in sheep, Elam.§§_§l, (1962) used 60% ground hay and 40% barley as the ration. The digestibility coefficient of dry matter determined by the total collection method was 65.4%. They observed highly signffiCant decrease in dry matter digesti— bility with increasing planes of nutrition. Wright and Grainger (1966) conducted a trial to observe the extent of post—ruminal digestion absorption of carbohydrates in mature sheep. A concentrate ration was 26 used. The results indicated that the ruminant possess an adequate capacity to digest carbohydrate post- ruminantly. They also indicated that starch was com- pletely digested and absorbed from the intestine. Cellulose digestion throughout the gastrointestinal tract was studied by Philipson 2; a1. (1942), Gray g; a1. (1947)! Hale g; 31. (1947), Gray §E_al. (1958), etc. Philipson g; a1. (1942) reported cellulose was fermented very slowly when compared to sugars. In another study sheep were fed a constant amount of wheat straw or lucerne hay and later slaughtered. Samples were taken from dif- ferent sections of the G.I. tract. The results showed that 40 to 45% of the cellulose present in the fodder was digested before the food passed into the abomasum and an additional 15 to 20% was digested in the large intestine. During the second fermentation 7 to 11% disappeared in the cecum and 4 to 9% in the colon. Approximately 70% of cellulose that was digested was broken down in the rumen, 17% in the cecum, and 13% in the colon (Gray 2E.§£~ (1947). Hale gt a_l.' (1947) studied the 0.14. digestibility by periods in the rumen. They demonstrated that soluble nutrients disappeared predominately in the first 6 hours of a 12 hour period. Cellulose was only slightly digested during the first 6 hours. They noted a more rapid degen- eration of cellulose during the second 6 hours than during the first 6 hours. 27 Gray 23 21- (1958) reported that the rumenal diges— tion of cellulose of sheep fed on wheat straw and lucerne hay was 30% and 50% of the total respectively; Yang and Thomas (1965) observed that D.M., organic matter and fiber were digested to a different extent in the rumen when rations consisted of two different levels of fiber in young dairy calves. The D.M. and organic matter of the high fiber rations were less digestible in the rumen than those of the low fiber ration. In a study with different kinds of forages, Van Soest (1965) observed that as acid detergent fiber (ADF) values increased from 24.8 to 54.8% digestibility decreased, A similar relationship also has been shown with the detergent lignin which ranged from 11.6 to 20%. In another study Van Soest reported that a fraction of carbohydrate contained substances which could be digested only by micro—organisms. He has shown that these types of carbohydrates were not completely available because of lignification. In general he suggested increasing maturity of plants lead to greater lignification and decrease in digestibility. Further he reported that alfalfa has rela- tively low cell wall content, which is highly lignified, while cell walls of grasses and straw form a greater pro- portion of the dry matter. A study was conducted by Ingalls g; l. (1965) to measure the digestibility and nutritive value index in 28 whethers-using different types of legumes and grasses. They found a positive correlation between lignin and D.M. intake, and a significant negative correlation between lignin or fiber content of the forages and percentage of digestible dry matter; In another study Ingalls gt 11. (1966) showed that rumen retention time of.D.M. was 0.65 days for legumes and 1 day for grasses. As intake of.D.M.. fiber, and lignin inoreased, retention time of each constituent decreased. Campling 25 El. (1966) conducted two experiments with cows fed artificially dried grass (highly digestible) and oat straw (poorly digestible) at restricted and at ad libitum rates of feeding. Cows were fed with long grass in the first trial and ground grass in the second. The results indicated that the rumen digestibility of organic matter of long dried grass was 74% and of ground dried grass was 67.7%. They reported that the digesti- bility of ground dried grass was much less than that of long dried grass when fed ad libitum. In this study the digestibility of crude fiber was 48.6% in cows fed dried grass, 43.2% for oat straw (long) and 54% for ground oat straw. Sectional studies of the G.I. tract in respect to dry matter absorption were made by few investigators using ruminants. Hale §t_al. (1947 b) reported that the average ruminal digestion coefficient as a percentage of total 29 was 48.4% for D..M.,59.6% for protein, 27.2% for crude fiber, 43.4% for cellulose, 83% for other carbohydrates and 3.1% for lignin. Similarly cecal coefficients were 11.6% for cellulose and 9.5% for protein. Weller g 31. (1954) reported extensive destruction of starch in the omasum. Wright and Grainger (1966) reported that starch was digested and absorbed from the intestine. Boyne 2; a1. (1956) observed that dry matter in the rumen decreased from 75% of the total in the tract just after feeding to about 60% 12 hours after feeding. They noticed that in the omasum the D.M., ash and energy concentrations of the contents were 50% higher than in the reticulo-rumen, and the nitrogen concentration was about 90% higher. In the small intestine they found that the D.M. content was 20% higher than in the abomasum and in cecal contents the concentration of D.M. was 40% greater than in the small intestine. Dry matter concentration was 60% higher in the colon than in the small intestine. Rogerson (1958) reported that absorption took place from the rumen. Badawy gt EA. (1958) demonstrated that the reticulo-rumen of sheep contained 74% of the total G.I. tract dry matter some four hours after feeding. They sug- gested that the dry matter percentage in the omasum was considerably higher in the omasum and the colon than in other parts of the G.I. tract due to water absorption. In another experiment they indicated that there was a 30 decrease in the dry matter percentage in the abomasum and suggested that this could be attributed to the dilution by gastric juice added (Badawy §3_al. (1958). Hogan and Philipson (1960) in an investigation with sheep demonstrated that the dry matter content of duodenal digesta varied from 3.3 to 7.1%,with a mean of 5.2%. Of the 66.2% that disappeared, 70% left the digestive tract between the mouth and pylorous, 11% in the small intestine and 19% in the large intestine. Yang and Thomas (1965) reported that absorption from rumen ranged from 51 to 86% for dry matter, 54 to 87% for organic matter, and 29 to 68% for fiber in the high fiber ration. They found no absorption for these materials from the omasum, abomasum, and upper small intestine. However, they observed absorption in the lower portions of the G.I. tract. Calves and goats fed milk replacer plus starter were used in a study by Heir 23 a1, (1968) to measure the ab- sorption in different sections of the G.I. tract. They observed that there was some net absorptiom in the reticulo— rumen and variable but moderate changes in the omasum and abomasum. They indicated that a large amount of dry matter were secreted in the upper 8.1. but re—absorbed in the remainder of the gut. Only little changes were noted in the cecum and large intestine in this study. 31 Topps §E_al. (1968) reported that 69% of the digesti- ble dry matter disappeared in the stomach (reticulo- rumen, omasum and abomasum), 17% in the small intestine, and 4% in the large intestine when fed concentrate and 67% of the digestible dry matter disappeared in the stomach, 22% in the small intestine and 11% in the large intestine when fed hay. Summary In many respects the gastrointestinal (G.I.) tract of ruminants is very complicated. In the G.I. tract of the ruminants, the rumen is the most complicated organ and its various functions are difficult to measure. Studies like digestion coefficients, absorption—secretion, retention time of particle of digesta, voluntary intake, rate of passage etc. have been made by many workers. Markers have been used for many years in measurements of digestion coefficients, rate of passage, retention time of particles of digesta etc. In recent years indicators have also been used to study flux pattern of various nutrients in different sections of the G.I. tract. The reference materials used‘in these studies include chemical compounds, radioactive materials, inert materials and natural constituents of plants etc. Most of these studies have been done using chromic oxide or lignin as the reference material. Digestibility comparisons made with both 32 indicators were satisfactory. However in a few sectional studies performed with ruminants there is the suggestion that chromic oxide might move out of the rumen at a more rapid rate than lignin or dry matter. Diurnal variations in excretion pattern have been noticed with both these indicators. Chromic oxide tended to have a highly sig— nificantly different diurnal pattern, while lignin showed only slight differences. Flux patterns of dry matter throughout sections of the G.I. tract have been reported by a few workers. Most workers reported that dry matter was mainly digested in rumen and about 25 to 80%Jwas absorbed from this organ. Further digestion and absdrption occurred in the cecum and large intestine. An endogenous secretion of dry matter has been reported for the proximal portion of the small intestine. Absorption and Secretion of Some Elements Through the G.I. Tract Sodium and Potassium Parthasarathy (1952) noted absorption of certain elements from the sheep alimentary tract. He showed that rumen sodium was absorbed against a concentration gradient while potassium was absorbed on account of its high con- centration in the rumen. In the other regions of the 33 alimentary tract sodium and potassium absorption from the small intestine and cecum were demonstrated. Field §§_§l, (1954) demonstrated that sodium was absorbed from the intestinal tract against a concentration gradient in humans. Visher §£_§l. (1945) reported that the lower part of the small intestine absorbed sodium against a concentration gradient. Absorption of sodium from the rumen was found by Dobson (1959) in sheep. He indicated that there existed a mechanism for active transport of sodium in rumen epithelium. He suggested that this inducing mechanism could drive the sodium into the plasma against a higher concentration and electrical gradient of this ion. Van Weerden (1961) in an experiment with cows Observed the absorption and secretion of sodium. He reported that sodium in the abomasum was much less than in blood, but he fofind an increase in the duodenum. Distally in the small intestine they observed that the concentration of sodium reached that of the blood in the distal end of the small intestine they noted that sodium concentration again declined and that it was much lower than that in the blood. This study suggested that in the lower part of the S.I., sodium was absorbed against a concentration gradient. Also they indicated that sodium can be absorbed from the large intestine against a concen- tration gradient. 34 Van Weerden (1961) demonstrated that the concen— tration of potassium along the intestinal tract was greater than that in the blood serum, so that absorption was not hindered by a concentration gradient. Yang and Thomas (1965) demonstrated that sodium was absorbed from the rumen and omasum and secreted into abomasum and upper section of the small intestine. They observed that reabsorption took place in lower sections of the small intestine. In calves Perry 23.31. (1967) studied the absorption pattern of sodium and potassium using different types of rations. They reported that there was no significant difference in the concentration of sodium in the rumen of the calves fed different rations (semi—purified, concentrate, and concentrate plus hay). Nevertheless they observed a high load of sodium in the rumen of calves fed concentrate and hay ration. The concentrate ration moved out of the rumen at a rapid rate and hence the sodium load for this ration was lowest. Also they reported a large secretion of sodium into the upper S.I. and absorp- tion of sodium throughout the remainder of the gut. Thus only 13% was absorbed from the cecum and large intestine. In the same way, Perry §§_al, (1967) indicated that 40% of the ingested potassium was absorbed from the rumen of calves that received the semi-purified ration and they suggested that this absorption was due to a high 35 concentration gradient resulting from the high potassium concentration in the feed. The percent of potassium intake absorbed in the rumen was 98, 75, and 80 for the semi—purified, concentrate, and the concentrate plus hay diet respectively. Calcium Wallace §E_§l, (1951) studied the extent of excretion of calcium from the G.I. tract in rats. He reported that most of the excretion of calcium occurred in the small intestine. Smith (1961) observed that absorption of calcium decreased with age in calves. Storry (1961) using sheep studied the distribution of calcium in contents of the reticulo-rumen, omasum, abomasum, S.I., cecum and colon. He observed that a considerable portion of calcium existed in a non-ultrafilterable form in all organs except the abomasum. He concluded from this study that the concentra— tion of non-ultrafilterable calcium was the main determinant for absorption. Storry (1961) reported that in the sheep rumen ultrafilterable calcium amounted to 20 to 60% of the total while in the abomasum it was close to 100%. Thus he concluded that calcium could be absorbed from abomasum at a greater rate than from any other sections of the G.I. tract. In calves, Chandler and Cragle (1962) studied the calcium and phosphorous absorption-secretion pattern. 36 They observed endogenous secretion of calcium into the omasum with a large net absorption from the abomasum. They further showed that calcium was absorbed in the first part of the 8.1., then secreted in the middle 8.1. and stayed fairly constant thereafter. Philipson and Storry (1965), using isolated sections of the small intestine, reported that losses of calcium occurred from the upper jejunum and middle of the 5.1. Cragle (1962) concluded that the major region for calcium absorption was the small intestine in calves. Perry g§_gl, (1967) reported similar results to those of Chandler and Cragle (1962) for endogenous secretion and absorption of calcium in calves. No net secretion was found in the omasum. Absorption of calcium was found in the abomasum. Also they reported some secretion in a few calves and suggested this could be due to the nature of the ration used. The major site of absorption however was the small intestine. They reported little change in the flux pattern of calcium in the cecum and large intestine. Magnesium Field (1961) studied the distribution of Mg in the G.I. tract and tissues of sheep. He demonstrated that the main site of absorption for Mg was in the middle third of the small intestine. Mg was secreted in this study in the first section of the small intestine and was approximately all reabsorbed from the lower segments of the 8.1. tract. 37 In sheep, Storry t al. (1961) reported that the principal site of absorption was the abomasum and the duodenum. Storry (1961 b) observed that ultrafilterable Mg in the rumen was about 20 to 60% of the total while that of the abomasum was around 100%. The proportion varied with pH. Ross (1962), by using an everted sac technique with rat's small intestine, reported that there was either a saturation process or a facilitated diffusion involved in the transport of Mg. Smith (1962) in a study with milk fed calves reported that in the G.I. tract the apparent absorp- tion of Mg ranged from 30 to 40%. Perry g£_al. (1967) observed an apparent net secretion of Mg in the upper small intestine in all calves. However they reported that net absorption occurred in the lower sections of the S.I. with little change thereafter. The average apparent absorption of Mg with all the rations in this study was 35%. Cragle (1967) demonstrated that there was no change in the ruminal concentration of Mg, while he indicated an apparent secretion of Mg in the upper S.I. in all calves used. Zinc Miller and Cragle (1965) used cows and older calves which were fed both hay and concentrate with ZN65 adminis- tered orally and showed that approximately 35% of the daily 38 administered ZN was absorbed from the abomasum. They observed that the secretion of Zn occurred in the first segment of S.I. but that absorption took place through the rest of the S.I. They indicated that little absorp- tion or secretion occurred below the cecum. In another study Miller (1967) determined the absorp- tion, excretion, and retention of orally administered ZN65 in various tissues of Zn deficient goats and calves. They noticed that the apparent absorption of Zn65 was 77.5% in the control calves and 83.2% for the Zn deficient ones by the end of 6 days. Absorption was 64.4% for control goats and 78% for deficient goats. Heirs jr. £5.31. (1968) studied the endogenous secre— tion and absorption of Zn in various sections of the G.I. tract of the Zn deficient and normal goats using chromic oxide as an inert indicator. In this study they observed that Zn’was secreted into the rumen followed by a variable amount of reabsorption in the abomasum. Also they have reported that a large pr0portion of Zn was secreted into the upper small intestine and absorbed in the lower portions of the S.I. Heirs jr. gg__l, (1968) measured the endogenous secre- tion of Zn in Holstein calves and in goats and observed that absorption took place in the omasum with a large secretion in the upper S.I. Reabsorption occurred in the lower sections of the small intestine. 39 Summary In ruminants it has been reported that sodium could be absorbed against a concentration gradient from the rumen (Parthasarathy 1952; Dobson 1959; and Yang and Thomas 1965). Absorption of sodium has been reported in the lower S.I. by Vischer §§.§l. (1945), Van Weerden (1961), Yang and Thomas (1965), and Perry $5.31. (1967). Few studies indicated an endogenous secretion of sodium in the upper S.I. (Van Weerden 1961; Yang and Thomas 1965; and Perry E; El. 1967). Absorption of sodium was also reported to occur from large intestine and cecum by these workers. Parthasarathy (1952) reported that potassium was absorbed from the rumen due to its high concentration. Also he indicated that absorption of this mineral was pos- sible from the small intestine and cecum. Perry §§_al. (1967) reported a 40% absorption of potassium from the rumen of calves fed a semi-purified ration. Van Weerden (1961) showed that potassium absorption took place from the small intestinal area. Smith (1961) reported that calcium absorption de- creased with age. Storry (1961) reported that calcium absorption could be maximum in the abomasum since calcium existed completely in an ultrafilterable form in this organ. Chandler and Cragle (1962) reported a secretion of 40 calcium in the omasum but an absorption in the abomasum and upper S.I. in calves. Field (1961) indicated that the principal site of magnesium absorption was in the middle S.I., while Storry (1961) suggested that this was in the abomasum and in the upper S.I. Perry 2; 31. (1967) and Cragle (1967) reported an apparent net secretion of magnesium in the upper small intestine. Few studies with Zinc in the gastrointestinal tract of ruminants indicated that some absorption of zinc occurred in the abomasum. Most of these studies also reported a high endogenous secretion of zinc in the upper S.I., and indi- cated reabsorption in the lower sections of the small intestine (Miller and Cragle 1965; Miller §E_al, 1967; and Heirs jr. 2; a1. 1968). EXPERIMENTAL PROCEDURES In previous work at this station sixteen sheep were used in a digestion trial (Bauman, M. S. Thesis, 1968). Rations used were siberian reed grass, reed canary grass, alfalfa early out (June 25th 1965) and alfalfa late cut (July 16th 1965). ’The sheep were fed the hay for a period of 20 days and then sacrificed. Eight were slaughtered at 6 hours and the remaining eight were slaughtered at 12 hours post prandial. These sheep were fed chromic oxide twice a day in a capsule. Both chromic oxide and lignin were then used as an indicator in measuring the absorption and or secretion of variOus nutrients (Miller and Cragle, 1965; Yang, 1964; Yang and Thomas, 1965; Perry §E_§l, 1967; Cragle, l967'etc.). The digestive tracts of sheep were removed soon after sacrificing the animals, and separated into nine different sections (rumen, omasum, abomasum, small intestine 11), small intestine (2), small intestine (3), cecum, large intestine (l) and large intestine (2). The contents of digesta from each of the above sections were removed, collected and weighed separately and dried. A portion of each sample from every section were used for analysis of 41 42 different nutrients and for chromium. The diet samples were also taken and a.portion analysed. The samples were then stored at room temperature for future studies. This experiment was designed to use the above mentioned samples for forages as well as the samples from the differ— ent sections to study several parameters. The parameters measured in this experiment were 1. The indigeStibility of different nutrients in dif— ferent sections of the gastrointestinal (G.I.) tract of sheep by using the lignin ratio technique. 2. To measure the flux pattern of different nutrients in the different sections of the G.I. tract by using lignin as the indicator. 3. To examine whether chromic oxide and lignin behave in a similar fashion in the different sections of the gastro— intestinal tract or to evaluate the suitability of both compounds as indicators for studying the flux pattern of nutrients in sectional studies of the G.I. tract in ruminants. Methods and Materials All the forage samples, and samples of digesta from the nine different sections already mentioned were ana- lysed in duplicate for acid detergent fiber (ADF), and acid detergent lignin (lignin) by the method of Van Soest (1963). Analytical values for minerals and dry matter were 43 taken directly from the thesis of Bauman (1968). Indigestibility of the following nutrients was de— termined by the lignin ratio technique (Ellis §t_al, 1946). The nutrients studied were Dry Matter (D.M.), Acid deter- gent fiber (ADF), Magnesium (Mg), Potassium (K), Sodium (Na), Calcium (Ca)f and Zinc (Zn). The flux pattern for. the same nutrients was calculated for the different sections of the G.I. tract. The digestibility of the nutrients and flux pattern for DD'M," ADF,’ Mg, and K were calculated for the forages fed. On the other hand the total Na, Ca, and Zn ingested by the animals represented not only the feed but other sources (mineral supplement and licking of galvanized pans). For this reason the feed equalled 100% for nutrients in the first category but rumen equalled 100% for nutrients in the second category. Calculation of Indigestibility Indigestibility of any ration can be defined as the portion which is not digested but is excreted through the feces. In sequential sectional studies however this would be the portion that entered into the next consecutive section of the G.I. tract. This indigestibility can be calculated by the lignin ratio technique by the following equation. 44 Equation 1 (% of nutrient in section) . . _ . Ratio (A of llgnln 1n sectron) Indlgestlblllty = Value 0% of nitrient in "Diet“) (% of lignin in "Diet") "Diet" used in the formula represented either “Feed" or the ”Rumen", depending upon the nutrient measured. For D.M,, ADF, Mg, and K the "Diet" represented the "Feed" value, while for Zn, Na, and Ca the "Diet" represented the "Rumen" value. The percentage of indigestibility can be obtained by multiplying the ratio value by 100. The digestibility value can be calculated from the indigestibility value given in figures and tables. For instance, digestibility of diet at the rumen would be 100 - (0.48 x 100) = 52%; at the S.I. (l) =~100 - (2.29 x 100) a -12.9% and at large intestine (2) 2 100 — (0.39 x 100) a 6L%. Flux Pattern of Nutrients Through the Different Sections of the G.I. Tract The absorption/secretion pattern of any nutrient could be studied by measuring the nutrients in the various sec- tions of the G.I. tract and expressing one in relation to the diet or to any previous organ by using Equation 1 (Yang 1964). 45 Absorption or secretion can be expressed as the "Net Flux", which would either indicate a net absorption or a net secretion from the diet to the organ. The net flux does not indicate the flux of a single section, but would show the net result of all fluxes in the previous sections. The measurement would help in finding how much of a nutrient is present in any particular section com— pared to the diet or shows the quantity of nutrient absorbed to the organ in question. Calculation of the "Apparent Flux” This term was used to compare the amount of nutrient in a designated section to that in the immediately preceding section. Whenever the value for "Apparent Flux" has a nega— tive sign (-), it means an "apparent secretion“ into that organ and whenever values have a positive sign (+) it indi- cates an "apparent absorption". In the presentation the + sign will be omitted. The calculation for net and apparent flux values are as presented below. Equation 2 Apparent Flux = (R.V of A - R.V of B) where R.V a ratio value obtained as per the first equation A a the previous section in reference to section designated as B B a the section in which the flux is measured. 46 These values were not presented for each nutrient but can be calculated from indigestibility values given in Tables 1 through 7. For instance in Table l the apparent flux from small intestine (l) to small intestine (2) would be 2.29 - 1.05 = 1.24 or from abomasum to small intestine (1) would be 0.45 - 2.29 = -1.81. Calculation of the Net Flux Equation 3 ”Diet". Section Net Flux = Ratio Value - Ratio Value. Where "Diet" Ratio Value is taken as 1 (Diet would mean either "Feed" or "Rumen" as defined previously). The value obtained for the net flux would show a net secretion whenever the value has a negative sign, and would show a net absorption whenever the value is expressed without any sign (omitted for this presentation). The Apparent Flux and the Net Flux can be expressed in percentage by multiplying those values by 100. Evaluation of Chromic Oxide and Lignin as Indicators Used in the Flux Pattern of Nutrients in Different Sections of the Gastrointestinal Tract of Sheep The flux patterns (apparent and net) of nutrients in different sections of the G.I. tract was compared using both 47 indicator. All nutrients and indicators were expressed on a dry matter basis. If both the indicators behaved in a similar manner, then the fluxes by the two indicators would show similar values. If there happened to be a dif- ference in these fluxes, then it would indicate that the indicators are not moving together. If the flux patterns show that there is a difference in fluxes, then the ratio between the two indicators would be different. A similar chromium/lignin ratio in the diet and in the different Sections would indicate that both indicators travelled at a similar rate. Also in such cases the ratio values among the sections should be the same. The data were analysed statistically by the analy- sis of variance to find whether there was any significant difference in the chromium—lignin ratio. The chromium lignin ratio was calculated for any section or for diet by using the following equation. Equation 4 Chromium/lignin ratio = chromium in ppm/lignin percent. A difference in chromium lignin ratios would indicate whether there existed a difference in the rate of passage of the two indicators used. However different chromium lignin ratios would not indicate which of the indicators moved differentially than the dry matter or water. In this study the rate of passage of these materials can be 48 estimated by calculating the proportion of dry matter, lignin and chromium present in each section of the tract or the distribution throughout the tract. Since the feeds and markers were given at the same time, this distribution should be related to the rate of passage of these materials. Hence a comparison of the distribution of lignin, dry matter and chromic oxide would give some information on the com— parative movement of these three ingredients. The comparison of fluXes in different sections, the chromium lignin ratio, and the distribution of dry matter, lignin and chromium were used to indicate whether both the indicators are suitable for different sectional studies of the G.I. tract. RESULTS AND DISCUSSIONS Dry Matter The indigestibility of dry matter (D.M.) is given in Table l. The base value for the D.M. has been taken as 1.00. The total D.M. indigestibility for the whole gastro- intestinal (G.I.) tract (feces) can be assumed to be the same as the lower portion of the large intestine. This averaged 39%. There Was considerable variation in indi— gestibility of this nutrient for the different sections. Analysis of variance indicated a highly significant differ- ence for the different organs at (P'< 0.0005). The indigestibility of D.M. at 6 hour and 12 hour after feeding is also given in Figure 1. On the whole the results show little difference but in certain sections rather large differences were noted. However, this difference was not statistically significant. Some variations in indigestibility were noted among forages for the whole tract. The grasses showed 66.5% digestibility while alfalfa showed only 41% (Table 1). This difference for D.M. was not significant. Indigestibility was larger for the late cut than for the early cut alfalfa (45 vs 37%). 49 50 .HMHHmumE wocmummmu mm seamed ADHB oocwfinouwo mosam> oaumu pom anatomumpmom munon NH Ho undo: o as omoflMHHomm ouoB momnm .mmmflm mo Donna Hmsflpmoucwouummm may moods wuaaanflummmaocH Houume hum .H musmflm 51 ANV.H.A muse: NH musoa o AHV.H.A H musmflm usmfimmm Downs moo.Ame.H.m Amv.«.m AHVMH.m uQ enIeA otisa 52 o.mm m.oo Masada m> mommmuo mo so so mo om so mo udoouom muaaaneumomen oo.o mm.o oo.o em.o oe.o om.o Hm.o Amemdaunmuda mound oe.o oo.o He.o me.o oe.o me.o no.0 Aaeodeunouda mound Ne.o me.o me.o me.o me.o He.o mm.o ssoomo oo.o an.o oo.o no.o oo.o oo.o mo.o Imeooaunouca aaoso No.0 ma.a oo.a -.H mm.a am.o an.o Amvodaumouda Hamso mn.a oo.~ mm.~ no.oa oo.a oo.~ oo.s Iavooaunouda Hanan oe.o oe.o oe.o oo.o mo.o oe.o me.o ssnnsona ee.o ee.o ee.o ne.o me.o me.o em.o ssnnso oe.o oe.o oo.o ne.o Ho.o ao.o ee.o steam mmmnm mumamo mmmum .o>m .o>m . .m>m Amanmov Amumav boom mundmo cmmuo .us «A .us o Hobos moamoad moaooad anemonao ooom .Houmofioca manaummmflosa no can: Gasman .Hawum>o mm HH03 mm mason NH can o 3009 How co>flm ma mmmno>mllmmo£m mo uomuu Hmswummusaouummm 030 Mo msowpomo unmummmao was: com msowumu usoummwflo Room 03p now Houpme hut mo mpfiaflnflumomHOGHll.a magma 53 The indigestibility of D.M. in the rumen averaged 48%. This amounted to 85.2% of the total. D.M. digesti- bility. There was not any difference observed in the indigestibility between the rumen values for the 6 hour period and 12 hour period (48% vs 48%). The rumen digestibility of grasses was 52.5% and 50.5% for the legume. Lignin content or structure may be a factor which makes the legumes more indigestible in this organ. Van Soest (1965) noted that alfalfa contained more lignin than the grasses. Increased maturity can also cause more indigestibility. In the omasum the average indigestibility of D.M. was found to be 44%. This decrease in the indigestibility might be due to the absorption of volatile fatty acids (VFA) and other nutrients in the omasum. There was no difference noted for the different hours. Digestibility to this organ of grass hay was 60.5%»and 52%lfor the legume hay. Indigestibility in the abomasum was 48% on an overall basis. There was no difference noticed between the 6 hour and 12 hour period in this organ. The higher indi- gestibility in this organ'than the omasum could be a result of "net secretion" into the abomasum. Digestibility for the grasses was 54.5% and 49.1%.for the alfalfa rations. In the upper small intestine the indigestibility averaged 229%. There was much individual variation in 54 this section. The difference between the 6 and 12 hour period was not statistically significant (285% vs 173%; P <:0.10). The grass hay was 228% indigestible while the legume was 621% in this organ. This high D.M. indigesti- bility in this organ was surely from other sources than the diet and could be assumed to be due to high amount of endogenous secretion into this organ. The indigestibility decreased considerably in the middle section of the small intestine indicating much absorption in this area of the small intestine. Both forages showed a similar trend. The average indigestibility in the middle S.I. was found to be 105%. The 6 hour period averaged 119% indigesti- bility, while the 12 hour period was only 92%. Little dry matter disappeared from the 6th to 12th hour. Legumes had greater indigestibility values in this section than the grasses (127 vs 84%). Digestion continued in the lower S.I. Indigestibility of D.M. in this organ averaged only 69% being 60% for the grasses and 78% for the legumes. Indigestibility was less at 12 hour than at 6 hour (66% vs 72%). In the cecum, indigestibility was found to be 42%. This could have been due to further digestion of D.M. by microorganisms. In this section there was no difference between the 6 hour and the 12 hour values. Indigestibility of grass hay was 38% and the legume hay 46%. The difference between the forages was not statistically significant. 55 There was little digestion in the large intestine. The overall indigestibility in the upper portion of the L.I. was 41%. The indigestibility for the 6 hour period was 43%, and the corresponding value for 12 hour was 40%. Only 33.5% indigestibility was noted for the grasses while the legumes was 42%. Total indigestibility at the lower portion of the large intestine showed 39% for the dry matter. In every section of the G.I. tract which was studied the 6 hour value indicated similar or more indigestibility than the 12 hour value. Alfalfa was more indigestible than grasses at all sections. The greater indigestibility value for the 6 hours can be explained by more digestion of fibrous material at 12 hours. However all the digestion for these nutrients could not be credited for the second 6 hour since these materials are digested to a certain extent within this first 6 hour period. Extent and rate of passage also influenced these values. Dry Matter Flux In the rumen the apparent flux showed 52% apparent absorption of the dietary dry matter (D.D.M.) which amounted to 85.2% of the total D.M. absorbed. In the omasum further absorption was observed. This apparent absorption on the basis of the dietary dry matter was 4% and on the basis of the previous section (rumen), the absorption was 8.3%. The VFAs are probably absorbed 56 in the omasum. Apparent secretion occurred in the abomasum. This amounted to 9.T% of the D.M. in the omasum. A large secretion was noticed in the upper portion of S.I. This amounted to 181% (apparent secretion) of the D.D.M. and 377% of abomasal D.M. This large secretion in the upper portion of S.I. must be due to a high secretion of D.M. from the endogenous sources. This endogenous source could be due to the high chloride ions, enzymes, and also from sloughing epithelial layers of cells etc. Considerable absorption or reabsorption occurred in the middle portion of the S.I. This absorption in the middle section of the small intestine amounted to 124% (2.29-1.05 x 100) on the basis of the D.D.M. Also this absorption amounted to 203% (124/61 x 100) of the total D.M. absorbed for the entire tract. In this section most of the enzymes, pancreatic juise, bile etc. would have had time to act on indigest D.M. and these absorption of the nutrients in this organ would appear likely. Further absorption continued in the lower S.I. This amounted to 34% of the D.M. present in the middle S.I. In the cecum and large intestine further absorption took place. Absorption in the cecum amounted to 27% of the D.D.M., 39.2% of the D.M. in the lower S.I. and 40.3% (27/61 x 100) of the total absorption of the entire tract. Absorption in the upper portion of the L.I. was 4.9%. 57 Acid Detergent Fiber (ADF) The indigestibility of acid detergent fiber is given in Table 2. The overall indigestibility of the ADF (ligno-cellulose) in the rumen was 58%. There was little difference in the indigestibility of this nutrient in the rumen for the two time periods involved (6 hour = 59% vs 12 hour = 57%). No statistical analysis was calculated for this nutrient. The grass hay ADF was 49.5% digestible while the alfalfa was 35%. In the omasum indigestibility was further decreased for this nutrient. The overall, the 6 hour, and the 12 hour indigestibility were all 48%, indicating some further removal of ADF in this organ. Digestibility of grass hay at the omasum was 6I% and the legume was 44%. As in the case of dry matter, ADF in the omasum also showed a higher indigestibility than in the previous section. The average indigestibility found in this organ was 53%. The 6 hour period averaged 54% and the 12 hour period 51% indigestibility. The legume showed 40% digestibility while the grasses 45.5%. The reason for digestion of ADF from grasses and not legumes in this organ may be related to differences in carbohydrate composition of these forages. In the entire small intestine the indigestibility averaged 52%. There was no difference found between the 6 hour and 12 hour periods. By the end of the lower S.I. 58 o.me so unmouom mmEsmva m> mommmuo mm mm mm ow as oo No udoouom musaanaunomao oe.o oe.o oe.o eo.o oo.o oe.o om.o Imemsaunmuda mound oe.o oe.o ne.o mo.o no.o me.o om.o racoseonousa mound oe.o oe.o se.o Ho.o oo.o me.o om.o enuomo mm.o mm.o oo.o no.o so.o oe.o me.o Amvoseunmuda Hamsm oe.o ao.o oo.o oo.o ao.o ee.o oe.o Invodaenousa Harsh mo.o oe.o me.o oo.o mo.o om.o om.o Iavodaunmusa Hanan Ho.o em.o oo.o no.o oo.o oo.o me.o ennmsond oe.o oe.o oe.o em.o oo.o om.o mm.o ennmso no.o oo.o oo.o mo.o no.o mm.o oe.o swans mumsmo .o>m .m>m .o>m Ahaumov Aoumav comm mnmcmo smmno .us as .us o Hobos boarded seaboad smauonao ooom .HOpmofloGH odnflpmomflocfl mm poms seamed .Hamuo>o mm. HH03 mm mason we com o spon How co>flm ma mmmuo>mllmmm£m mo uomnu Hosaummosfloupmmm may mo mcoapoom DGTHTMMHU mafia 6cm mCOHumu usouommao noon map How Amndv omoasaaoonosmfla mo auflaanflumomaosH .m magma 59 the digestibility of ADF in grasses was 56%, and of the alfalfa ADF 39.5%. Further digestion of ADF occurred in the cecum. The overall indigestibility in this section was reduced to 47%. Values for the large intestine however did not indicate any further digestion of ligno—cellulose. In this organ the upper portion showed 47% indigestibility, while the lower portion showed 48%»indigestibility. The digestibility of ADP in the rumen of these sheep averaged 42%. In the cecum further digestion by bacteria probably occurred as indicated by an additional 11% digestion of ADF. The overall indigestibility of ADF for the entire tract was 48%. At this point the two time periods did not show any differences in the indigestibility of this nutrient (6 hour a 48%, 12 hour a 48%). The differ- ences in ADF digestibility of grasses for the whole tract was 61% and the corresponding value for alfalfa was 43.5%. Flux Pattern of ADF In the rumen the lignin indicator method showed that there was 42% disappearance of this nutrient. From rumen to the omasum a further disappearance occurred which amounted to 10% of the dietary ADF, and 17.3% of this nutrient present in the previous section. In the abomasum a 5%.secretion occurred which reduced the net absorption to 47% in this organ. 60 Some apparent absorption was found in the upper portion of the small intestine. Absorption in this section was due to the value found for the 6 hour period. The net absorp— tion was found to be 50% for ADF in the small intestine. In the cecum disappearance occurred. The net disappear- ance in this section changed to 53% from 50% in S.I. In the large intestine there was no further change in the flux pattern. The net disappearance of ADF for the entire G.I. tract amounted to 52%. Magnesium Data in Table 3 indicate that on an average the total indigestibility of magnesium (Mg) for the entire tract was 62%, being 63% for the 6 hour period and 6T% for the 12 hour period. Statistical analysis indicated some difference between the time periods (P mommmno mm am on oa mm on no odoonod suaaanaunmmao Ho.o mo.o ~o.o eo.o no.o we.o nm.o Amvmdaumopda mound no.0 ~o.o mo.o oo.o on.o Ho.o so.o Aavodaunouda mound oo.o No.0 so.o om.o Hh.o mm.o o¢.o Esuomo No.0 m¢.o mm.o Ho.o mm.o mm.o m~.o Amvmsflummucfl HHmEm mm.o om.o ¢¢.o mm.o mm.o Hm.o Hm.o Amvosaumoucw Hamam mv.o mo.o mm.o mo.a m¢.o Hm.o om.o Advocflumouca HHmEm ma.o oa.o va.o va.o NH.o mH.o mH.o EsmmEon< mH.o ma.o mH.o mH.o 5H.o «H.o ¢H.o Edmmao ma.o oH.o ma.o ma.o oa.o oH.o oa.o smEdm wumcmo .m>m .o>m .0>m Ahaummv Amumav comm humcmo cmmuo .Hn NH .HQ 0 Hmuoa mmammad mmammdd cosmonflm 60mm .uoumoaosa manannooaona mm poms Gasman .Haoum>o mm H603 mm undo: ma com o anon How so>wm ma ommum>0|lmoonm mo uomuu Hmsflumousflouummm map mo mcoauomm ucoHTMMHo mass was mcoaumm usonmmmao snow on“ How Esamocmma mo muflHHQHummmHocH .m magma 62 than the indigestibility of the legumes (grasses = 40.5%, legumes = 75%). Statistical analySis indicated that the forage (grass and legume) differed significantly (P‘< 0.01) in the indigestibility of Mg in the S.I., cecum, and large intestine. Flux Pattern of Magnesium In the rumen Mg appeared to be highly absorbed. The apparent absorption of Mg in this section amounted to 85% of the mineral present in the diet. Storry (1961) indicated that 20-60% of total Mg can be found in the rumen in the ultrafilterable form and hence can be absorbed from this section. In the omasum no change occurred in the flux pattern. In the abomasum the net flux showed 86% net absorption but only l% compared to that present in the omasum. Storry (1966) demonstrated that in the abomasum Mg existed almost 100% in an ultrafilterable form and hence would be available for maxium absorption. In this study net absorption in this section was also high. The apparent flux in the upper S.I. showed a large apparent secretion while the net flux showed 43% net absorp— tion. There was a 13% apparent absorption in the middle S.I. while the net flux for the lower S.I. showed a 48% net ab- sorption. An apparent secretion of Mg has been reported in the upper S.I. in sheep (Field 1961) and in calves (Perry e; a1. 63 1967; Cragle 1967). The middle portion of the S.I. was found to be the major site of Mg absorption. A similar result has been reported by Field (1961). Mg absorption may involve both active and passive transport. Ross (1962) using everted S.I. sac technique with rats reported that there is either a saturated active process or a facilitated diffusion involved in the transport. Apparent flux in the F cecum showed a 20% apparent secretion, while the large , intestine showed little apparent absorption. The apparent absorption in both the sections of the L.I. amounted to 1% If each. On the whole the net absorption of Mg in the G.I. tract was 38%. Smith (1962) demonstrated a similar result. He showed an apparent absorption of Mg for the entire G.I. tract of milk fed calves ranging from 30 to 40%. Perry “£3.31. (1967) reported 35% apparent absorption of Mg in calves. Potassium Table 4 shows the indigestibility of potassium (k) for the different sections of the G.I. tract. Analysis of variance indicated afhighly significant difference for the different organs (P‘< 0.0005). On the whole, the result showed little difference between the 6 and 12 hour period (6 hour = 9%, 12 hour = 8%). Some variations in digestibility were noted among forages for the whole tract. The lignin indicator technique 64 m.mm unmouom moEfimuH m> mmmuo Ho so so mo om so so bemused moaaanaunomao oo.o oo.o oo.o no.o ¢H.o oo.o oo.o Amvooaumouda mound -oH.o oa.o oH.o ea.o ma.o ea.o oa.o Advocsuoouda mound na.o ma.o oa.o ma.o ma.o va.o NH.o Esoomo m¢.o Nv.o m¢.o m¢.o so.o mm.o mm.o Amvosaumouca HHmEm mo.o om.o mm.o so.a mm.H sm.o Hm.o Amvosflummusa Hamam mm.a ms.m H¢.m mm.h bh.a on.a mm.o Aavmsaummucw Hamam Hm.o sm.o mm.o om.o mm.o sm.o Hm.o Edmmaond mm.o m~.o mm.o mm.o mm.o mN.o om.o Edmmeo Hm.o sm.o ~m.o mm.o om.o em.o hm.o coesm mumgmo .o>m .m>m .m>m Ahauoov Aoumav oomm wnmsmo smmuo .Hn NH .Hn o HMUOB mmammafl mmammad cmaumflam comm .uoumoaosa manaunomaoda no new: seamed .Hamnm>o mm Ham3 mm mH50£ NH com o soon How cm>wm we mmmum>MI|mmm£m mo uomup Hmsflumoucaouummm mnu mo msowuomm usmnommao was: pom mcoaumu ucoHGMMHo snow mnp How Edammmuom mo hyaaflnflumomHUgH .v manna 65 showed a significant difference in the indigestibility of potassium in the upper S.I. (P‘< 0.05) due to forage dif- ference (grasses vs legumes). The indigestibility of potassium in the rumen averaged 32%. Rumen digestibility amounted to 35% of the total potassium digestibility. There was slight difference in the indigestibility between the values for the 6 hour period and 12 hour period (34% vs 3P%). The digestibility of K in grass was 70% and 66% in the legume. In the omasum the indigestibility was reduced little (29%) and there was no difference between the time periods (29% vs 29%). In the abomasum the indigestibility increased slightly and reached the value previously shown in the rumen (32%). In the upper portion of the small intestine secretion of K was found (24T%) and this value was greater in this section than all other sections of the G.I. tract. Also at this point the two time periods demonstrated a higher vari— ation in indigestibility than other sections of the G.I. tract. This amounted to 343%, and 139% respectively for the 6 and 12 hour periods. On the whole the indigestibility of potassium for the entire small intestine was only 42%. In the cecum the average indigestibility was found to be only 16% indicating that 84% of the dietary potassium disappeared prior to entering the large secretion. In the lower L.I. the value for the indigestibility was further reduced. At this point the average indigestibility was 9%. 66 The Flux Pattern of Potassium In the rumen the flux pattern of potassium showed 68% absorption. Parthasarathy (1952) and Parthasarathy and Philipson (1953) have reported absorption of K from the rumen. They suggested that potassium is absorbed from rumen on account of its high ruminal concentration compared to its concentration in blood. Sperber and Hyden (1952) suggested that potassium could passively diffuse across the rumen epithelium. In the omasum and the abomasum the flux changed little. The net absorption for abomasum amounted to 68%. The apparent flux for the upper S.I. showed 209% apparent secretion and the net flux 141% net secretion. In the middle portion of the S.I. the apparent reabsorption amounted to 159%.. The net flux at the end of the large intestine showed that 91% of dietary potassium was absorbed. Perry e§_al. (1967) also reported similar results for potas- sium absorption in calves. After a large endogenous secretion in the upper S.I. absorption continued throughout the remainder of the tract. Sodium The indigestibility of sodium (Na) is given in Table 5. The sectional studies indicated that there was considerable variation in the indigestibility of Na in different organs of the G.I. tract. Analysis of variance indicated a highly 67 m.mo on unmoumm moenmod m> mumso as oo me up No on me pooouom suaaanaonomaa m~.o em.o o~.o mm.o om.o Hm.o nm.o racosaunouda omumd oo.o Ha.a ao.e oo.o ao.e oH.H oo.o lacosaunouda mound HH.H mm.a -.H Ho.a o~.H em.a v~.H ssommo as.m mm.m mo.m ov.~ ne.m om.~ oo.~ Amvodaunouda Hamsm mn.~ me.v oo.o He.m H~.a oo.m em.m Ameodaunousa Hamso oo.v ~o.m oo.o o~.oa so.v om.o .no.e Aavodaunouda Hamsm on.o mo.a Hm.o oo.o oo.o mn.o oo.o esnmsoss oo.o oo.o mm.o no.0 so.o me.o ne.o ssnmso oo.H oo.a oo.a oo.a oo.a_ oo.a oo.a doses mumcmo .0>m .o>m .m>m Amaumov AwumHV woom mumamo cmmno .ns we .us o emuoe noemoea seasons seasonao ooom .HODMUHUcfl manwumomflocfl mm poms seamed .Hamuo>o mm Ham3 mm mason NH can 0 Quon How Gm>Hm ma mmmum>MIlmoonm mo uomuu Hmcflumwucflonumwm map mo moosuoom possummso mass was mcoflsmu #GTHTMMflU snow was How Eswoom mo husaaflfiummmfiocH .m magma 68 significant difference for the different sections (P< 0.0005). The total indigestibility of Na for the entire G.I. tract (up to L.I. (2)) averaged 28%. The indigestibility of Na at 6 hours exceeded the 12 hour value (34 vs 23%, P < 0.10). a The overall digestibility of Na from the two forages did not show any significant differences. The digesti- bility of Na from grass hay showed on an average of 76% “‘4‘“? ' .‘I'fixvln r—. while the same for legume was 69.5%. T7 In the omasum the average indigestibility of sodium was 52%. In the abomasum the indigestibility was 91% for sodium. The 6 hour period indicated 105%.and 12 hour period indicated 76%. The digestibility of Na in the abomasum was 14.5% for grass hay and 5% for legume. The average indigestibility of sodium in the upper small intestine was 685% due to high endogenous secretion. The two time periods also showed much variation in the indigestibility. The 6 hour value was 962% indigesti- bility while the 12 hour value was 408%. The average indigestibility of Na decreased considerably throughout the remainder of the intestine. The average indigestibility in the cecum was 122% and this was reduced further to 28% by the time it reached the lower L.I. Values for each forage as well as the two time periods followed a similar decrease in the indigestibility of sodium. 69 Flux Pattern of Sodium The flux pattern of sodium has been measured in the different sections of the G.I. tract after the rumen. In this calculation the rumen value represented the base value. The apparent flux of sodium in the omasum showed a 48% apparent absorption, while value in the abomasum showed a 39% apparent secretion. ”The net flux at the end of the abomasum was a 9% net absorption of sodium. In the small intestine, the magnitude of apparent flux was much greater than any other section. An apparent sodium secretion of 594% was calculated for this section. In the middle S.I. an apparent absorption of 321%, and in the lower S.I. 62% apparent absorption Were calculated. Yang and Thomas (1965) by using lignin ratio technique demonstrated an absorption of Na in the rumen and omasum and secretion in abomasum and in upper S.I. In their study also the secretion obtained in the upper S.I. was of a higher magnitude than the values shown in any Other section. In the lower S.I. these authors showed a large reabsorption of Na. In the present study the small intestine was divided into 3 sections and hence the flux was measured more accur— ately. The middle portion showed greater absorption of Na than any other section. Reabsorption continued, in the lower S.I., cecum and large intestine. This is different than the study of Yang and Thomas (1965). However they 70 indicated that their observed secretion into the large intestine and cecum might have been due to other reasons (experimental errors). Perry 22.él- (1967) showed similar results as found in this study in dairy calves. They showed that a large secretion occurred in the upper S.I. and absorption of sodium.occurred throughout the remainder of the gut. They also indicated that 13% of sodium was absorbed from the cecum. In this study the net absorption of sodium on the basis of rumen value was found to be 78%. Yang and Thomas (1965) reported that total absorption of sodium ion was 69 to 89% for the entire tract. Calcium Data in Table 6 indicate that the average total indi- gestibility of ruminal calcium (Ca) for the total G.I. tract was 182%. Analysis of variance indicated a highly significant difference for the different organs (P<< 0.0005). The two time periods on an aVerage indicated very similar indigestibility for the entire tract (6 hour = 183% and 12 hours = 182%). The average indigestibility of grasses was 152%, and the corresponding value for alfalfa was 198%. Statistical analysis by the analysis of variance indicated this difference was significant at (P<< 0.10). The indigestibility of calcium in the omasum averaged 153%.being 152% for the 6 hour and 155%1for the 12 hour time period. In the abomasum the indigestibility value .WA‘. .¢ :1. .fiy‘ Ill 71 mm: m.mm| seamed m> mmmno mm. mm. No- no- mm. as. so- unwound suaaanaunomao No.a mo.a mo.a no.a oo.a we.a ao.a Amoodeumousa mound mm.a oo.a om.a na.m na.~ oo.a oe.H Aaeoseonoosa omens em.e mm.e om.e na.~ m~.~ ao.a ee.a snoomo mo.~ ma.m ea.~ ea.~ oo.~ eo.e mn.a Invosaonoesa Hanan mo.e os.~ No.e ma.~ oe.~ oo.e oe.a Amvmdaunoosa Hanan mm.s om.~ He.m me.m Ha.m ao.e He.a revosaunousa Hanan oo.o as.o am.o eo.e es.o oo.o oo.o enhanced mm.e No.a mo.a no.e mo.e em.e Hm.e enumeo oo.H oo.H oo.e oo.s oo.H oo.e oo.e omens mumsmo .m>m .o>m .o>m Ahaumov Amumav poem mumsmo smmuo .us as .us o Hobos moemoed oneness seasonao ovum .HoumososM manaumomflvsfl mm toms sasmaq .Hamnm>o mm HHQB no muson NH ram o Suon How cm>sm we ommnm>muumoo£m mo uomnu audaummucfiouummm 030 mo msoauomm psoHTMMHU mass has moospmu ucmummmwo snow was How ESAUHMU mo hasaaflwumomsosH .o magma 72 decreased on the average as well as for different hours (averaged = 8l%, 6 hour = 77%.and 12 hour = 85%) indicat- ing some absorption occurred in the abomasum. In the upper S.I. the indigestibility reached the maximum (24l%) when compared to other sections. This was probably due to endogenous secretion of calcium. The indigestibility was reduced to some extent in the middle S.I. (192% from 241%). However by the lower value for indigestibility had again increased to 211%. A similar trend of decreasing and increasing the indigestibility value was noted for both time periods. In the cecum and large intestine the indigestibility values decreased slightly. On the average, the cecum showed 198% indigest— ibility for calcium while the two sections of the large intestine had values of 196% and 182% respectively. Flux Pattern of Calcium The rumen value represents the base value for calcium. In the omasum the flux pattern showed that a net secretion occurred and in the abomasum a net absorption was noticed. Chandler and Cragle (1962) observed an endogenous secretion of calcium in the omasum with a large net absorption from the abomasum. In this study the endogenous secretion in the omasum was 53% (net secretion). Abomasal absorption amounted to 52.9% of omasal calcium. Smith (1961) reported that calcium existed in the abomasum in an ultrafilterable . 73 form and hence could easily be absorbed. Perry g§__l, (1967) could not find a net secretion of calcium in the omasum, but did show that calcium was being absorbed from the abomasum. In the upper S.I. calcium was found to be further secreted. The apparent flux indicated an apparent calcium secretion of 160% and a net secretion of 141%. Reabsorp- tion occurred in the middle S.I. This absorption amounted to 79.6% of the calcium present in the S.I.(l). In the lower S.I. further apparent secretion was noticed (19%). I'H7 This is similar to the observed apparent secretion of Mg for this organ (Table 3). Apparent flux for the cecum, L.I.(l), and L.I.(2) were 13%, 2% and 6%.respectively. The net flux at the end of the small intestine showed llT% secretion. By the end of the large intestine the net flux indicated 82% net secretion of ruminal calcium. Perry gg_al, (1967) showed that major site of absorp— tion of calcium was the S.I. They also indicated that very little change occurred in the flux pattern of calcium in the cecum and large intestine. Zinc The indigestibility of Zinc (Zn) is given in Table 7. The base value for Zn has been taken as 1.00 for the rumen. The ruminal Zn indigestibility for the whole G.I. tract mil .;-i. : 74 m.mm| hm: mesmwa m> mmmno om- mm- on- so- mean won on: bemused sueaanaumomao oo.a mm.a on.a so.a ma.~ oo.a oe.H Amvodaunouda momma oo.a oo.~ Ho.a os.a so.m oe.a oo.a Iaemdaumouoa mound so.a ma.m mm.a vm.a mm.m mm.a on.a Edommo mm.a mm.m HN.N om.a ¢~.m mo.m on.a Amvmsaumousa Hamam ma.m «m.¢ oN.m ma.m N¢.m ~¢.N oo.m Amvmsspmmuss AHMEm mo.¢ mm.aa 05.5 Hm.om Hm.m oo.o bv.¢ Advoswumousa HHmEm om.a Hm.o saga mm.a oa.a mH.H No.a Edmmeonm mo.H OH.H mo.a no.a omoa om.o no.0 Edmmeo oo.H oo.a oo.a oo.H oo.a oo.H oo.a smasm mnmsmo .o>m .w>m .o>m Amaummv Aoomav poem hnmcmo smmuo .ns NH .us o Hmuoe hostess moamoed omanmnao ooom .HODMUHUGA manflummmfloCH on com: seamed .aamuo>o mm HH03 mm mason NH Ugo o soon How sm>am ma mmmnm>mnlmmm£m mo Dummy Honeymoussouummm one mo msowuomm econommao mass osm moosumu psoummmwo snow 0&0 How UGHN mo musaanaumomsosH .n oaflma 75 averaged 178%. Analysis of variance indicated a highly significant difference for the different organs (P‘< 0.0005). The average indigestibility of Zn by the 6 hour and 12 hour time periods showed some differences for the dif- ferent sections. In certain cases these values varied widely. Statistical analysis for the two time periods were not cal— culated. On an average the 6 hour period showdd 199% indigestibility for Zn for the entire tract while the 12 hour value was 156%. On the whole, legume was more indigestible than grasses (legume = 183.5%, grasses a 144%). Indigestibility of Zn in the omasum was 108% and 114% in the abomasum. The indigestibility of Zn for the abomasum as indicated by the 6 hour and the 12 hour time periods was 91% and 136%, respectively. The 6 hour period showed some absorption of Zn, while after the second 6 hour period the value indicated secretion. Maximum indigestibility of Zn was noticed in the upper S.I. Both time periods indicated increases in this section. The increased indigestibility of Zn was found to be more pronounced for the 6 hour time period (ll38%) than the 12 hour period (40l%). In the later sections of the small intestine indigestibility of Zn decreased. In the cecum and large intestine Zn indigestibility was further reduced. A similar pattern was noticed for both time periods and for all four forages. However the indigestibility value found indicated that Zn excretion was greater than ruminal Zn, 76 even though most of the endogenous Zn was absorbed. Since fecal Ca and Zn exceeded ruminal amounts these must have been ruminal absorption of dietary Ca and Zn. Flux Pattern of Zinc The rumen value represented the base value in this study. The apparent flux of Zn in the omasum showed an 8% apparent secretion. It has been reported that Zn absorption occurred in the omasum and the abomasum (Miller and Cragle, 1965; Heirs jr. §£_§1, (1968). In the upper portion of the small intestine the appar— ent flux amounted to a 656% secretion. Large secretions of Zn in this section have been reported by several workers (Miller and Cragle, 1965; Miller g; a1, 1967; Heirs jr. ggual. 1968; etc.). However secretions of this magnitude have not been reported. In most reports the indicators used were either chromic oxide or radioisotopes. Probably the difference showed could be due to the indicator (lignin) used in this study. More research with both types of these indicators would be necessary for substantiation. Most of the endogenous Zn which was secreted in the upper S.I. was absorbed in the lower portions of the small intestine. Only slight amount of absorption occurred in the cecum and large intestine. Of the 656% of apparent secretion in the upper S.I., 67%.was absorbed in the middle S.I. and 16% absorbed in the lower S.I., 4.3% absorbed in the cecum and only 1.7% and 0.2%.absorbed in L.I.(l) and 77 L.I.(2), respectively. Thus the middle S.I. was the major site of zinc absorption. In general there appeared to be a trend in showing some difference between the forages with respect to the indigestibility in the sections of the G.I. tract (legume vs grasses). The difference was more pronounced with g minerals such as magnesium, calcium, potassium and zinc and generally this great difference in indigestibility was shown in the small intestine. Concentration of these dif- ferent minerals vary in grasses and legumes. In legumes calcium concentration and magnesium concentration are generally higher than grasses, while Zn and K are generally lower than grasses. However the difference shown in indigestibility between sections could not be due to the difference in concentration but could be due to some other factors. Some organic compounds in the G.I. tract could combine with these minerals and make their digestion or absorption difficult. Mineral absorption of legumes are often affected in this way and many inorganic compounds formed in the small intestine can associate with those organic compounds to influence their absorption. It has been reported that inorganic phosphates, iron, stronium, Berillium etc. influence indigestibility of calcium. Ca, K, and Mg are interrelated. 78 Flux Pattern of Nutrients as Shown by Lignin and Chromic Oxide Method for the Different Sections of the G.I. Tract of Sheep The net fluxes of 6 different nutrients were compared by the lignin and chromic oxide method and the results were plotted graphically (Figures 2 through 7). For the dry matter the apparent fluxes were also calculated as shown in Table 8. These values were not tested for the statistical significance. Using the lignin indicator the rumen showed a 52% apparent absorption of D.M. The Cr203, however, showed a 76% secretion of D.M. into the rumen. In the rumen the indicators showed a divergent result of a high magnitude. Over the years many pe0ple have shown that dry matter is digested and absorbed in the rumen (Hale §L_gl. (1947); Gray gt_§l, (1947);‘Kane §t_§;, (1950); Bolin §§_§l. (1956); Rogerson (1958); Badawy (1958); Hogan and Philipson (1960); Yang and Thomas (1956); Topps §t_§l, (1968); Erickson gt 3;. (1970); etc.). The range of dry matter absorbed or digested in these studies was from 20 to 75% and for this section alone the dry matter absorbed might be up to 85%. In this study the values indicated by the lignin method were found to be in agreement with those reported in the literature. The high secretion suggested by chromic oxide for dry matter in the rumen is questionable since a high endogenous secretion of dry matter into the rumen is 79 .muoumoHUcH mm cflcmfla com moflxo UHEOHQU moans >9 omuommme mm momsm mo uomuu .H.w map mo mommuo pneumMMflo ms» afl.uoupme who mo cumuumm xsam one .N musmflm N musmfim ucoEmmm uomna 80 Ame.H.q AHV.H.q + . oeflxo xHEouao shaman mmo ’ ‘ Amv.H.m ANV.H.m AHV.H.m 1| ond Sm + enTeA oraeu 81 .muoumoflGCfl mm cflcmwa cam mcflxo anOHQO moans an cmusmmme mm mmmSm mo uomuu .H.w may mo mcwmuo ucmummwflc map ca Esflmocmme mo cumgpmm xSHM one .m mnomflm 82 E v.3. E .m... 0.00 Ia: u.-J.1.. .‘ 1|...3 Ha fl‘i w m Guzman .ucmsmmm.uomua. Amv_H m A~V_H m Am~.H m mcflxo unsouno shaman 0 at u 0.0 1r L.m.o 1‘. L... -O.H enIeA orqeu 83 .mHOOMUH@CH mm cacmfla 6cm moflxo UflEouflo mcflmo ma cousmmme mm mmmnm mo uomuu .H.O may mo mommno HGOHOMMHU on» :fl Esflmmmuom mo cumpumm XDHM 0:8 .¢ whomflm 84 m . . a. . 0:.‘113... _ ..... ....L..Hrlfl v mHsmHm ucmammm uumua 331438.44 Jmo 37m...“ 33H...“ A318. on... . so am an 0 moflxo owsouao 0 II it at Gasman n enIeA orqeu 85 .muoumuaccfl 0:» mm cflcmfla Ucm mpflxo Ofleonso moans ma ownsmmme mm mooam mo uomup .H.O map mo mammuo ucoHOMMHp Gnu CH ESHUOm mo cumuumm xsam one .m musmflm 86 .2 m mndmflm pcmsmmm uomna mnwxo UHEoufiu n ANV.H.A AHV.H.q mmo AmV.H.m ANV.H.m AHV.H.m chm so am no ‘ _ r — Ll _ — Pl . _ .. /I D Pl 3 . o.H . - o.m r 00m .3. Gasman u x x enTeA otqeu 87 .muoumoflUCH may mm cacmfla cam moflxo UHEOHQU an consumes mm uomuu .H.0 may mo mammuo ucmuwmwflw mnu CH Eofloamo mo cuwuumm xsam OQB .0 mudmflm ANV.H.A Adv Ilr .Hofl _ UMU _ 88 @ musmflm pnosmom uomua AmV.H.m Amv.H.m AHV.H.m r . _ enteA 01423 L mcflxo xfleouno fl - 4| Gasman HILTILTI!. 89 .mHOHMUflUCH may mm GHGOHH cam mwflxo UHEouflu an ©0H5mm05 mm momnm mo pumuu .H.w man we mommuo OGOHOMMHU m3» GH UGHN mo cumuumm xSHw $38 .5 musmflm 90 n musmflm ucmEmOm uumua ANV.H.A AHV.H.A mmo AmV.H.m ANvoHcm AHV.H.m 03¢ . 80 um “Q L h . F . r _ _ p 4 0.0 a .O.N AVOOv .o.® voom mcwxo UflEOHflU HIJII4III Canada "IITIITI. enIeA orqeu Table 8. The flux pattern of dry matter in the different organs of the G.I. tract of sheep as measured by using chromic oxide and lignin as indicators. Apparent Flux Net Flux f Organ (digestibility) Cr Lignin Cr. Lignin i Rumen —0.76 0.52 -0.76 0.52 ‘ Omasum 0.80 0.04 0.08 0.56 Abomasum 0.41 -0.04 0.49 0.52 S.I.(l) -1.81 -1.81 —1.32 -1.29 S.I.(Z) 1.03 1.24 —O.29 -0.05 S.I.(3) 0.48 0.39 0.19 0.34 Cecum 0.31 0.24 0.50 0.58 L.I.(l) 0.00 0.01 0.50 0.59 L.I.(2) 0.01 0.02 0.51 0.61 92 not likely. Yang (1964) indicated that when chromic oxide was used as an indicator in absorption/secretion studies of different nutrients, in the rumen dry matter flux showed a similar secretion as in the present study. Lignin, however, indicated a considerable absorption of dry matter in the rumen. This difference must be due to some differential passage between the two indicators. In the omasum the apparent flux by lignin indicated 4%.absorption while the flux using chromic oxide indicated 80% absorption. In general, absorption of dry matter has been reported in the omasum, this however is usually a fraction of what has been shown for the rumen. The value shown by chromic oxide in this section is unlikely to occur in the omasum. The absorption indicated by the lignin method appears reasonable as well as close to what has been reported in the literature. A slight secretion of 4% was demonstrated for abomasum by the lignin method. In the abomasum chromic oxide indicated an apparent absorption of 4r%. The net flux nevertheless did not show much variation (49 vs 52%) between the values indicated by both the indicators. Therefore either of these indicators could be used to study net effect from diet in the abomasum. In the small intestine, the apparent flux shown by both lignin and chromic oxide amounted to a secretion of 18E%. Also a very similar pattern occurred throughout the remaining 93 sections of the S.I., cecum, and large intestine. A more or less similar pattern of flux could be seen between the two indicators for the other nutrients (Figures 3 through 7) also. The difference shown by the two indicators in the flux of nutrients, especially in rumen and omasum strongly suggested that the variation was mainly due to the indiCators used. Differences in the rate of passage of these indicators could account for the different ratio values in each section. Chromium/Lignin Ratio The average ratio for chromium to lignin in the dry matter for the 16 sheep are given in Table 9. The flux comparison of different nutrients in different sections of the G.I. tract by lignin and chromic oxide methods sug— gested that the difference found could be due to differences between the two indicators. Many indicators have been used to study different parameters in digestion trials, rate of passage, retention, etc. The comparisons of markers in such studies were done to evaluate the dependability of these markers as well as their accuracy for that purpose. Recoveries of markers in feces, and comparison with total collection methods generally indicated the merit of the marker used in such studies. However in studies for observ— ing the flux pattern of nutrients through the G.I. tract recovery of markers in the feces is not a valid basis for comparing indicators. 94 Table 9. Average chromium/lignin ratio of 16 sheep in the different sections of the G.I. tract. Location Ratio Diet 4.14 Rumen l.l9 Omasum 2.25 Abomasum 3.93 S.I.(l) 4.25 S.I.(2) 3.31 S.I.(3) 3.32 Cecum 3.48 L.I.(l) 3.39 L.I.(2) 3.13 95 The chromium/lignin ratios could be used as one of the best estimates of the differential rate of movement of these indicators throughout the G.I. tract. The data indicated that there existed some difference in this ratio between the diet and the various sections. Further, it also pointed out that there was a difference among the ratio values among various sections. Statistical analysis by the analysis of variance indicated that these differences in the sections were highly significant (P