A study has been made on the growth stimulatory-effect of antibiotics when fed to chicks as supplements to different rations. A total of 9 biological tests employing 1280 chicks were carried out. Chicks fed the Connecticut ration and modifications thereof showed a significant growth response to aureomycin supplementation of the rations. The efficiency of feed utilization was improved by the addition of aureomycin to the rations in this experiment. The effect of aureomyoin has been tested in rations in which the protein level has been adjusted to 16%, 17.9%, 19.5% and 22% respectively. The basal rations used consisted of ground corn and wheat as the cereal grain and soybean oil meal and fishmeal as the protein supplements along with additional vitamins and minerals to balance the ration. The results showed that aureomycin did not lower the dietary requirement of the chick for protein. A test was made on the effect of antibiotics on growth of chicks when fed in rations which were deficient in specific amino acids. A wheat ration deficient in lysine and a corn ration deficient in tryptophan have been used. The results showed that antibiotics did not lower the dietary requirement of the chick for either lysine or tryptophan. Antibiotics were fed in chick rations containing different amounts of available carbohydrates. It was found that antibiotics did not lower the dietary requirement of the chick for carbohydrate. A comparison of aureomycin and penicillin showed no difference in growth stimulating properties between the two antibiotics under the conditions of the different experiments. Aureomyoin supplement (aurofac) promoted the same growth response at 0.05 and 1.0% levels. The greatest growth response to antibiotics was obtained when the chicks were fed a diet adequate in available carbohydrates and protein and balanced in amino acids. / Land and Food Systems, Faculty of / Graduate

The physiological effects of excess vitamin A are frequently studied in the investigation of the systemic function of the vitamin. The liver vitamin A storage efficiency of dietary excesses of vitamin A and the effect of excesses of the vitamin on alimentary cholesterolemia, the one-stage prothrombin time and the one-stage euglobulin lysis time were investigated in several genetically distinct populations of chickens. Birds of a New Hampshire (NH) line were found to store vitamin A in the liver from the diet more efficiently than birds of three White Leghorn (WL) strains (D,K and B) and of one broiler strain. An excess of dietary vitamin A reduced alimentary cholesterolemia in the NH chicks but increased alimentary cholesterolemia in the D chicks. There was no effect of hypervitaminosis A on the blood cholesterol concentration of either the D or the NH chicks receiving a low-cholesterol diet. No carryover effect of vitamin A upon removal of the excessive quantity of the vitamin from the diet, could be demonstrated on alimentary cholesterolemia in either the D or the NH chicks. The efficiency of the intestinal absorption ofcholesterol was increased in both the NH and the D chicks by an excess of vitamin A. The liver-to-blood partition ratio of cholesterol was increased by excess vitamin A administration in the NH chicks, but was decreased by excess vitamin A in the D chicks. The one-stage prothrombin time of D,K,B, and NH chicks was unaffected by the dietary administration of large excesses of the vitamin from day-old to three weeks of age. Chicks of a Black Australorp (A) line, however, responded to large excesses of the vitamin in the diet with an increase in one-stage prothrombin time. A single intramuscular injection of menadione (5 mg/kg body weight) brought the prolonged prothrombin times of the A chicks to normal within twenty hours. The one-stage euglobulin lysis time of NH,D and A chicks was decreased by the inclusion of large excesses of vitamin A in the diet of the birds from day-old to six weeks of age. Intramuscular administration of menadione (5 mg/kg body weight) was without effect on the shortened lysis times within twenty-four hours. Removal of the excessive quantities of vitamin A from the diet for six weeks failed to affect the shortened clot lysis times of the A hypervitaminotic chicks. Vitamin K deficiency induced in a Shaver strain of WL chicks by feeding the birds a K-deficient diet, had no effect on the euglobulin lysis time. The results of the present experiments extend knowledge of the effects of hypervitaminosis A on the induction of alimentary cholesterolemia and on the blood coagulation mechanism in the chicken. / Land and Food Systems, Faculty of / Graduate

The effect of heat treatment on the protein quality and the metabolizable energy value of rapeseed meal was investigated. Different rapeseed meal samples were autoclaved at 121° c for different times. a significant reduction (p < 0.05) in the in vitro protein digestibility resulted from the autoclaving treatment. Further reduction in protein digestibility occurred when samples were autoclaved with glucose. Poor growth and feed efficiency in the chicks were observed due to feeding of autoclaved rapeseed meal ration. Lysine supplementation of autoclaved and unautoclaved rapeseed meal improved growth and feed efficiency. Maximum growth on the control ration was obtained with 0.16% lysine supplementation whereas 0.24% maximized the growth of chicks on autoclaved rapeseed meal. No significant effect was observed on liver weight expressed as percentage of body weight, however, pancreas weight was significantly greater (p < 0.05) in birds receiving autoclaved rapeseed meal than the controls. There was no significant difference in metabolizable energy value of autoclaved and unautoclaved rapeseed meals. / Land and Food Systems, Faculty of / Graduate

Experiments were carried out to determine the effect of breeder diet on the weight of the chick at hatching and up to 4 weeks of age and on the effect of breeder diet and chick diet on body composition of the chick. The dietary treatments imposed were related to protein level and amino acid composition of the breeder diet and the chick diet. Two experiments were carried out in which different sets of dietary comparisons with breeder rations were made. In the first experiment, diets fed to the breeders varied with respect to the source of supplementary protein (soybean meal, herring meal and white fish meal) supplied. The progeny of these breeders showed differences in hatch weight but the differences in weight were no longer statistically significant by the end of the first week after hatching. The breeder diet did not appear to affect the composition of the progeny at hatching or at three weeks of age. In the second experiment the diets fed to the breeders differed markedly in protein level as well as in amino acid composition and in this experiment there were significant treatment effects on the hatch weight of the progeny which persisted until at least four weeks of age. In a third experiment chicks were fed different levels of lysine and the effects on body weight and on weight of the pectoral muscle measured. It was found that the weight of pectoral muscle was more sensitive to dietary lysine level than was total body weight. It was therefore concluded that the ratio of pectoral muscle weight to body weight provides a more sensitive criterion of the lysine adequacy of a chick diet than does body weight. In further study of the effect of the amino acid balance of the breeder diet on embryonic and postnatal growth of progeny the use of this ratio as the criterion of response should be investigated. / Land and Food Systems, Faculty of / Graduate

The present study consisted of three sections each of which was undertaken to obtain information on some aspect of protein quality evaluation by biological testing. The first study consisted of two experiments in which the free amino acids were determined in the plasma of birds fed cereal diets to determine if this method would indicate the amino acid adequacy of the diets. The second study was an investigation of the use of chicken muscle meal as a reference supplementary protein. The third study consisted of an investigation of the fractionation of intestinal nitrogen as a method for studying protein quality. In the first series of experiments in which plasma free amino acids were determined to investigate protein quality two groups of White Leghorn chicks each were fed a control diet consisting of a high protein wheat diet supplemented with 0.24% lysine and 0.06% methionine and the control diet further supplemented with 0.1% L-arginine and glycine and 0.045% L-leucine and L-threonine. Blood samples were collected from birds on each diet after a 14 hour fast and after 3 hours and 6 hours of ad libitum feeding following the fast. The PFAA patterns obtained at both 3 and 6 hours after commencement of feeding from chicks which had been fed these two diets for three weeks indicated a lysine deficiency. The 6 hour plasma pattern from chicks fed the supplemented diet showed a greater percentage of threonine and less of the other EAA except arginine in comparison with the pattern seen in the plasma from birds fed the control diet. Lysine was shown to be the first limiting amino acid in diets containing 10.7% crude protein (N x 6.25) from wheat and 4% crude protein from rapeseed or soy bean meal by growth test and PFAA patterns. After 3 hours of ad libitum feeding different levels of circulating lysine were observed in the plasma from birds fed the rapeseed diets supplemented with 0.15% lysine. The levels of circulating lysine were not significantly different due to sample variation, but in general the higher levels of plasma lysine were seen in birds with the heavier body weights. A single level of supplementation was inadequate to determine the next limiting amino acid in these diets. In an investigation of the use of chicken muscle meals as a reference supplementary protein various chicken muscle meals were compared to an isolated soy protein and methionine reference supplement. The meals were prepared by freeze drying either cooked or raw tissue. One meal was treated with antioxidant. Diets containing 8% protein from the protein supplement and 10% protein from the wheat basal diet supported as good growth as that obtained with a good quality commercial fishmeal when tested at the same level of supplementation. All the chicken meals and the fishmeal supported better growth than the ISP and methionine reference control. A few small trials to investigate the use of gut nitrogen levels for evaluating protein quality were carried out. Preliminary trials included the determination of the nitrogen recoverable after the administration of different test meals with different protein sources, carbohydrates and fiber. Results obtained after administering single test meals were not considered reliable. A method was used where by the intestinal contents were sampled one-half hour after several meals had been administered and the nitrogen fractionated into TCA soluble and insoluble portions. When the amount of recoverable nitrogen insoluble in TCA was taken as the criterion of quality, differences were demonstrated between a sample of good quality protein supplement and one of extremely poor quality. Less of the nitrogen recovered from birds fed a high percentage of fiber in the test meals was soluble in TCA than when the protein was fed with corn starch or glucose mono-hydrate. The amount of liquid in the slurry was found to affect the amount of nitrogen recoverable if several feedings were administered in a relatively short period of time. Once the biological method was established preliminary determinations of the amounts of recoverable free basic amino acids from the intestinal segments were carried out. Generally a greater number of micromoles of basic amino acid per segment were found in the jejunum than in the ileum. In some cases there was less of these amino acids present in the gut of birds fed protein with glucose monohydrate than from the gut of birds receiving other treatments but this may only have been due to the effect of the liquid in the slurry. It was recommended that pellets would be a more biologically accurate method to administer the test meals. / Land and Food Systems, Faculty of / Graduate

A study was made of the effects of feeding excess vitamin e to chicks. Three groups of experiments were conducted to investigate (1) thyroidal response to excess vitamin e, (2) respiration rate of muscle mitochondria from chicks fed excess vitamin e; and (3) symptoms of hypervitaminosis e. In two separate experiments, chicks were fed normal and excess levels (220 i.u./kg. of diet) of vitamin e and were subjected to temperatures of 14.5 and 31.5°c. the goitrogenic effect of thiouracil on the birds in the different treatments was measured. At both temperatures the thiouracil-treated chicks fed excess vitamin e exhibited a lesser enlargement of the thyroid glands than did chicks receiving a normal level of vitamin e. This finding indicates a reduction in the secretion of thyroid stimulating hormone (tsh) in birds fed excess vitamin e. the level of vitamin e which was fed did not affect the growth rate or feed consumption at either temperature. It, therefore, appears that the metabolic rates of the chicks fed the low and excess levels of vitamin e were similar despite differences in thyroid activity and that tissue respiration in birds fed excess vitamin e can be maintained with a reduced supply or turnover of thyroid hormone. The activity of the thyroid gland itself was studied in response to excess vitamin e in another experiment. Using radioiodine (l¹³¹) as a tracer, it was found that the rates of iodine uptake and release by the thyroid gland were both slower in birds fed excess vitamin e (220 i.u./kg. 0f diet) than in control birds. Because vitamin e acts as a biological antioxidant, it may, in excess amounts, depress the rate of oeiodination of thyroxine in the peripheral tissue at which thyroid hormone is removed from the circulation. As a consequence, the secretion of tsh would be reduced. In order to obtain some indication of cause and effect in the mechanism by which the excess vitamin e affects thyrotropic hormone secretion rate and thyroid activity, the respiration rate of mitochondria isolated from the pectoral muscle of chicks which had been fed excess vitamin e (2200 i.u./kg. 0f diet) was compared with that of the control birds. The results showed a significant reduction in oxygen uptake by the muscle mitochondria of chicks fed the excess amount of vitamin e. The growth rate of the chicks fed the excess level of vitamin e in this experiment was markedly lower than that of the control chicks. It is suggested that the chick may maintain a normal respiration rate when fed excess vitamin e up to a certain level through a reduction in thyroid activity. With a large excess of vitamin e, however, no further compensation is possible. and respiration rate is depressed below normal. Excess vitamin e caused hypoprothrombinemia, indicative of vitamin k-deficiency. Other symptoms noted were a reduction in hematocrit values, reticulocytosis and an abnormally fluid appearance of the bone marrow. Based upon observations of bone calcification, the calcium requirement appeared to be increased in the presence of excess vitamin e. / Land and Food Systems, Faculty of / Graduate

The effects of various dietary treatments on metabolic responses related to adrenal functions have been studied in growing white leghorn chickens. Birds fed a diet containing 20.9% of protein and deficient in lysine (.51%) showed higher plasma c0rticoster0ne concentrations, increased adrenal size, and increased oxygen consumption compared with birds fed a diet of similar protein content and adequate in lysine (1.11%). Birds fed the lysine-deficient diet showed more exploratory behaviour when placed on a grid than did the birds fed the diet supplemented with lysine. They took a longer time, however, to locate feed in a maze. Thiouracil with hypervitaminosis e, administered to birds through the diet, increased the concentration of corticosterone in the plasma. Hypervitaminosis e did not affect the concentration of corticosterone in the plasma. The concentration of c0rticoster0ne was similar in the plasma of chicks reared at 13 and 24°c. / Land and Food Systems, Faculty of / Graduate

Male and female broiler-type chicks were subjected to different periods of dietary restriction between the ages of 0 and 14 weeks of age. Feed was restricted during this period of time by limiting feed consumption to 30 minutes of feeding per day. Growth rate of the birds and mature body weights were measured. The proportion of organs and tissues, and adipocyte diameter and number in the retroperitoneal and M. sartorius depots were determined in mature female birds subjected to the different periods of dietary restriction. The following summarizes the findings: 1. Male and female birds subjected to different periods of dietary restriction from 0-14 weeks of age had similar body weights at the end of any given period of feed restriction. However, following ad libitum feeding, the male birds previously subjected to different periods of dietary restrictions, grew at a greater rate and obtained a greater final body weight than did the females. 2. Dietary restriction increased mortality in both male and female birds. There was, however, no sex difference in mortality in response to the early dietary restriction. Cropbound birds and birds with leg weakness accounted for most of the mortality. Dietary restriction from 0-12 and from 0-14 weeks of age caused significant decreases in the mature body weights of female birds. The lighter weights appeared to be due to a reduction in the growth of all tissues since the proportional -weights of the M. pectoralis major, liver, tibiotarsus, retroperitoneal and M. sartorius adipose depots were similar in the restricted and the control birds. The tibiotarsus and the M. sartorius adipose depot were the tissues most sensitive to the dietary restriction. Since the weight of the retroperitoneal adipose depot was not significantly affected by dietary restriction, there may be differences in the responses of the retroperitoneal depot and the M. sartorius depot, to early dietary restriction. Determining the average, retroperitoneal adipocyte diameter at 17-19 weeks and 40-43 weeks of age, revealed that adipocyte enlargement in the retroperitoneal depot occurred in all treatments between the) two ages. Adipocytes from the retroperitoneal depot were significantly larger than adipocytes from the M. sartorius depot regardless of dietary treatment. Dietary restriction reduced the average adipocyte diameter in the retroperitoneal and the M. sartorius depots of birds subjected to dietary restriction from 0-12 and from 0-14 weeks of^age; and the effect on cell size was still apparent at 40-43 weeks of age. 7. Adipocyte cellularity in the M. sartorius depot was similar for all treatments studied, indicating that the number of adipocytes in this depot was unaffected by early dietary restriction. In the retroperitoneal depot, however, birds restricted from 0-12 and from 0-14 weeks of age had significantly more adipocytes than did the control birds. Whether this increase in observable adipocytes reflected an increase in adipocyte cellularity or an increase in the lipid-filling of pre-adipocytes is not clear from this study The difference in response to early dietary restriction exhibited by the retroperitoneal and the M. sartorius depots may reflect a greater propensity of adipocytes in the retroperitoneal depot to multiply. / Land and Food Systems, Faculty of / Unknown

Chicks were utilized in a study to estimate mineral (Ca, P, Mg, Mn, Cu and Zn) availability of 10 meat meal samples processed in 10 consecutive days. A balance procedure was used to determine availability in which a correction for endogenous mineral was utilized. Results of this study indicate that calcium and phosphorus are highly available from meat meals with values of 90% and 93.4% respectively. Magnesium, manganese, zinc and copper are also well utilized with an average of 83.9%, 73.1%, 79.4% and 74%, respectively. Variations in availability of minerals particularly phosphorus, copper and zinc were observed among meat meal samples tested. This indicates that raw material used in day to day manufacturing of the meals are different; also, phosphorus might exist in different forms from one meal to another. Availability values observed in this study indicate that meat meal is an excellent source of available minerals. The important mineral (Ca, P, Mg, Mn, Cu and Zn) content was determined in blood meal, feather meal, fish meal and meat meal. These availability studies utilized the broiler chick (three weeks of age) in a mineral balance procedure. Results of mineral content showed a wide range in Ca (2.1-84.0 mg/g), P (1.9-54.0 mg/g), Mg (12.5-68.0 mg/kg), Cu (8.3-22.4 mg/kg) and Zn (22.7-1 50 mg/kg). The range in concentration of Mg among samples was narrow (1.3-2.7 mg/g). Blood meal was the lowest in all minerals except Cu. Fish meal #1 and fish meal #2 or meat meal were the highest in these minerals. Significant variation was observed in availability of each mineral among animal protein concentrates tested. Average availability of Ca, P, Mg, Mn, Cu and Zn was 88.3, 87.6, 80.8, 71.7, 73.2 and 76.8, respectively. Studies were conducted with broiler chicks to compare the availability of phosphorus from feather meal, blood meal, meat meal and fish meal using different assay techniques. A standard curve was drawn by plotting the growth rate and percentage of tibia ash obtained at various levels of added dicalcium phosphate (Reference diet). The biological availability of phosphorus for animal protein concentrates was calculated from the standard graph. When body weight was used as a criteria the comparative availability of phosphorus from feather meal, blood meal, meat meal (L), meat meal (H) and fish meal was found to be 91%, 112%, 118%, 123% and 125%, respectively. The comparative availability of phosphorus from feather meal, blood meal, meat meal (L), meat meal (H) and fish meal when percentage of tibia ash was used as a criteria was found to be 84%, 98%, 112%, 121%, 121%, respectively. The percentage of tibia ash obtained with test phosphate was divided by the percentage of tibia ash obtained with standard phosphate. When this method was used to calculate the comparative availability of phosphorus from feather meal, blood meal, meat meal (L), meat meal (H) and fish meal, the calculated values were found to be 85%, 90.5%, 94.7%, 97.3% and 97.3%, respectively. The availability of phosphorus from feather meal, blood meal, meat meal (L), meat meal (H) and fish meal was calculated using mineral balance procedure and was found to be 72.5%, 88%, 92%, 95%, 95.3%, respectively. This study indicates that variation in the procedure used to determine phosphorus availability from animal protein sources may influence data. / Land and Food Systems, Faculty of / Graduate

Content and availability of nutrients in ten wheat feed screening samples were determined using day old broiler chicks. The metabolizable energy (ME) value of wheat feed screenings (WFS)in a balanced diet was significantly (P > 0.05) higher than wheat which was used as a control diet. Growth performance of all WFS samples were higher than control diet. Diets one, two, four, seven, ten and eleven had feed efficiency ratipswhich were significantly (P > 0.05) higher than the control diet. The total average availability of sixteen amino acids in these feedstuffs ranged from 66% (control) to 84% (diet three). Among limiting essential amino acids, lysine was significantly (P > 0.05) higher (83%) in availability followed by threonine (67%) and methionine (64%). The average availability of the studied chemical elements (Ca, P, Mg, Mn, Cu, Zn) ranged from 59% (Zn) to 84% (Cu). Among the chemical nutrients tested, copper (84.28%) was the highest to be followed by manganese (76.57%) and phosphorus (74.14%) and the least was zinc (59%) in availability value. The results of these studies indicated that WFS has an acceptable potential to replace wheat with reasonable margin of profit to the producer. / Land and Food Systems, Faculty of / Graduate