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

Immature chick oviducts differentiate in vivo in response to daily injections of DES. This is indicated by increases in general oviduct protein nitrogen: DNA ratios and the production of immunologically precipitable ovalbumin. Three types of ovalbumin are produced in response to estrogen. These results indicate that ovalbumin free of phosphorus appears first in the oviduct tissue in response to DES. The appearance of phosphorus containing ovalbumin follows. Attempts were made to induce the in vitro differentiation of oviduct tissue under a variety of culture conditions. A standard culture media was supplemented with DES and serum (fetal calf, cockerel, laying hen, or chick serum) as well as serum from DES injected chicks. No changes were observed in the tissue histology nor in the production of the specific protein, ovalbumin, under the above conditions. Closely associated tissues such as kidneys, ovaries, mesentary or ureter tissue cultured with the oviduct tissue failed to elicite any detectible morphological and chemical changes in the latter. The addition of insulin or homogenized pituitaries from DES injected or non-injected chicks was ineffective as an inducer of differentiation in this system. Substituting 17 6-estradiol for DES as an inducer did not alter the results. Thus, with the exception of estrogen any factor(s) necessary for the in vivo differentiation of immature oviduct tissue remains unknown at this time. / 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

Egg shell quality was assessed in terms of breaking strength, elasticity, and energy absorbed by the shell up to failure. Two devices were used to determine these characteristics. Simple correlation and simple linear regression analyses showed that elasticity as determined by either device gave equally reliable estimates of breaking strength of the egg shell (r = -.68). A study of the three calcium levels supplemented to a basal ration on shell quality of eggs from two reciprocal crosses of birds showed that each measurement (breaking strength, elasticity, and energy to failure) used to assess shell quality produced different conclusions. In the early part of the experiment, elasticity was significantly lower for the 2% than for the 4% or 6% calcium diets in both crosses of birds. However, there was no significant difference in the effect of 4% and 6% calcium diets on elasticity. On the basis of the energy absorbed to failure, there was no significant effect of dietary calcium in Cross I birds. In Cross 2 birds, 6% calcium produced significantly superior results on energy absorbed as compared to the 2% and 4% calcium diets. For Cross I birds, breaking strength of eggs from the 6% and 4% dietary calcium treatments were significantly higher than those from the 7% calcium treatment. For Cross 2 birds, 4% dietary calcium produced stronger shells than 2%; shell strength from the 6% calcium treatment was inter, mediate to and net significantly different than that of the 2% or 4% calcium diets. No significant difference in the effect of the three calcium diets on shell quality as assessed by any one of the three measurements was observed in the latter part of the experiment. No consistent effect of the age of birds on egg shell strength was apparent. Significant variation in shell strength was found among groups of birds within the same cross on the same ration. Eggs stored under selected environmental conditions for different durations showed that moisture affected egg shell elasticity and the effect Increased In magnitude with time of storage when the egg was not only Immersed in water but also filled with water after removal of the albumen and yolk. Neither oiling nor storage temperature affected egg shell elasticity. There was no consistent effect of storage duration on egg shell elasticity except for the two treatments in which eggs with or without the contents removed were stored under water. It was found that the difference between the two duplicate elasticity readings measured at the equator of the same egg did not change significantly with either storage condition or storage duration. / Land and Food Systems, Faculty of / Graduate

An in vivo technique was developed for the purpose of determining the rate of absorption of bile salts by the mesenteric small intestine of the chicken. Using this technique, it was found that the absorptive capacity of the intestine for sodium taurocholate and sodium glycocholate increases distally. The possibility was investigated that the amount of bile salt reabsorbed from the intestine determines the level of circulating sterols in the chicken. Intestinal absorption of sodium taurocholate was accordingly determined in birds selected to show a wide range in levels of circulating sterols. Absorption of the bile salt was tested with concentrations of taurocholate equivalent to 0.15 and 0.75% cholic acid, using open segments of intestine. Data obtained from 20 birds showed that the level of circulating sterols and the rate of bile salt absorption were not significantly correlated. The lack of a significant correlation was considered to be probably due in part to variation in the effect of diet on the availability of bile salts for reabsorption. The rate of bile acid excretion and the concentration of circulating sterols were therefore determined in birds fed diets supplemented with triglycerides, of varying degree of unsaturation, soyalecithin and beta sitosterol. It was found that a diet supplemented with 15% coconut oil induced an elevation in the level of plasma sterols when substituted for a low-fat diet but that diets supplemented with corn oil and herring oil, induced little or no change in this level. The change to a fat-enriched diet was associated with a decrease in the fecal output of bile acids. The decrease was greater when coconut oil rather than corn oil or herring oil was fed, indicating that the plasma sterol lowering property of unsaturated fats is due at least in part to their enhancing effect on bile acid excretion. Diets to which 2.5% soyalecithin and 0.5% beta sitosterol were added, effected a slight reduction in the level of plasma sterols. The addition of soyalecithin to the diet resulted in a significant increase (P < 0.01) in the growth rate of the birds studied. The amount of bile acids excreted was increased significantly (P < 0.01) by the addition of soyalecithin to the diet. The addition of beta sitosterol to the diet resulted also in an increase in bile acid excretion. The increase approached significance at the 5% level of significance (F ratio calculated = 7.53, significant F ratio = 7.71). The increase in bile acid excretion resulting from the administration of the soyalecithin supplemented diet was considered to be the net result of two opposing effects. One effect was an increase in the reabsorption of bile acids. It was evidenced by a further increase in the plasma sterol level of the lithocholic acid-fed chick in response to dietary soyalecithin. The other effect was reasoned to be an increase in the biliary excretion of bile acids and/or bacterial alteration of bile acids in the digestive tract. / Land and Food Systems, Faculty of / Graduate

Experiments were conducted to study the effect of dietary lysine level on thyroid activity and body temperature in White Leghorn cockerel chicks. Thyroid activity was measured in birds 4-to-5 weeks of age and body temperature was measured in birds 4-to-8 weeks of age. Three diets based on corn and sesame meal and containing 20% protein and 0.64% (basal diet), 1% (control diet) or 2% of L-lysine respectively were used. These diets contained deficient, optimal and excessive amounts of L-lysine respectively. Thyroidal experiments were conducted at different times of the year. Thyroid activity was assessed by measuring the level of I¹³¹ in the plasma and thyroid or thyroid only at various times after an intravenous injection of 0.55 μc of I¹³¹ 100 gm of body weight. In August-September, thyroidal response to diet was investigated in birds fed the test diets for either 1 or 17 days prior to administration of I¹³¹. When the test diets were fed for 1 day prior to the injection of I¹³¹, data for per cent I¹³¹ per unit of thyroid weight and for the ratio of thyroidal to plasma I¹³¹ (T/P ratio) indicated that either a deficiency or an excess of dietary lysine enhanced thyroid activity. Feeding the test diets for 17 days appeared to attenuate the responses observed in the 1-day trial. In January, thyroidal response to diet was assessed in birds fed test diets either 1 day before or 3 days after the injection of I¹³¹ . Only the diets containing 0.64% and 1% of L-lysine were fed. When appropriate, 0.2% thiouracil was added to block thyroidal uptake of recycled I¹³¹. When all four diets were fed, I¹³¹ level per unit of thyroid weight and T/P ratio calculated from data obtained 5 minutes, 1 and 3 hours after I¹³¹ administration indicated that dietary lysine deficiency under the circumstances of the experiments reduced thyroidal uptake of the isotope. When I¹³¹ was injected 3 days prior to imposition of the test diets, the values for I¹³¹ per unit of thyroid weight after the feeding trials started indicated that the lysine deficiency reduced the rate of release of thyroidal I¹³¹. In a further experiment, levels of thyroidal I¹³¹ measured 5, 10, 24, 48, and 72 hours after I¹³¹ injection verified that the lysine deficiency reduced thyroid activity. In March, the effect of ambient temperature on thyroidal response to dietary lysine level was investigated. Thyroidal I¹³¹ was measured 6 hours after I¹³¹ administration to birds which had been fed the deficient diet for 1 day. Dietary lysine level and environmental temperature had an interacting effect on total thyroidal I¹³¹ and per cent I¹³¹ per 100 gm of body weight. Under the conditions of the experiment, lysine deficiency enhanced I¹³¹ uptake in a warm environment but has no effect or depressed activity in a cold environment. Temperatures were measured with thermistor probes inserted into the cloaca, the brain and the pectoral is muscle. When fed for either 18-to-30 hours or for 2 weeks, the lysine deficient diet increased muscle temperature. The diet had no apparent effect on brain or cloacal temperature but detection of a response may have been obviated by the technique used to measure temperatures in these two locations. Feeding sub-optimal or excessive levels of dietary lysine for only 1 day caused a change in thyroid activity. In a warm environment, both sub-optimal and excessive levels of lysine enhanced thyroid activity. Environmental temperature appeared to modify the thyroidal response to dietary lysine level. In a warm environment, a deficiency of lysine increased muscle temperature. / Land and Food Systems, Faculty of / Graduate

A study was conducted to make a genetic evaluation of egg mass (weight of the total eggs laid in a given period) in order to determine its genetic potential as a new criterion for selection as compared to the conventional selection program based on egg number (early and full production records). In addition, biometrical evaluations of some egg component traits: yolk weight, albumen weight, shell weight, percent yolk, percent albumen, percent shell, albumen percent solid, yolk percent solid, yolk percent protein, albumen percent protein, yolk solid and albumen solid were made. The aforementioned traits were measured on 3 random bred lines of chickens in quarterly periods through the laying year. Within each line, the heritability estimates of egg number and egg mass for any given period (275, 325, 450 and 540 days of age) were found to be in close agreement. In general, for egg number and egg mass, selection from early production records showed higher gains per unit of time than full year production records, A negative genetic correlation between egg number traits and egg weight traits and a positive genetic correlation between egg mass and egg weight traits was found, therefore, selection for egg mass was recommended. Relative merit of early and full year egg records as selection criterion was discussed in the light of the results obtained for the three lines. It was concluded that the decision as to which criterion should be used would have to depend upon the genetic properties of the population in question. Line effects were found to be significant for all the egg component traits studied, except percent shell, A season-age effect was also found to be significant in all the traits studied. Season-age by sire interactions were found to be non-significant for all the traits in all the three lines. The importance of yolk size from a human nutrition standpoint was discussed. A selection program based on total yolk weight produced by a hen in a given period (yolk mass) was suggested. Because of the water in the egg being an essential nutrient for the developing chick embryo, it was suggested that selection be made on the egg solid or egg solid mass (total amount of solid laid by a hen in a given period). The heritability estimates of albumen percent solid and albumen percent protein were high and of the same magnitude. It was, therefore, suggested that an increase in percent protein in albumen should be achieved by selection of albumen percent solid. / 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

Five hundred and seven random bred New Hampshire chicks, the progeny of 15 sires each mated to 3 dams, were used in the study. The per cent gamma globulin levels obtained, 12.38%, 10.92%, 11.47%, 14.24% and 15.37% at hatch, 1, 3, 5 and 7 weeks of age respectively, followed a trend consistent with the literature. The drop from hatch to 1 week of age (12.38% to 10.92%) was attributed to the loss of maternal antibody coupled with a corresponding low rate of synthesis by the chick. From 1 to 7 weeks of age the per cent gamma globulin level increased although the values at 1 and 3 weeks were not significantly different. The relatively large increment from 3 to 5 weeks of age (11.47% to 14.24%) was consistent with a report in the literature. The within variance component obtained from the analyses of variance on the data of each age group considerably increased from 1 to 7 weeks of age. The sire and dam variance components showed no consistent trend, only a week to week variation. A considerable maternal affect at hatch was suggested by the sire (h2/s = -0.33) and dam (h2/d = 1.53) estimates of heritability. The analysis of variance on the combined data from 1 to 7 weeks of age resulted in a sire estimate of heritability (h2/s) of 0.26 and a dam estimate (h2/d) of 0.67. It was concluded that the additive genetic contribution accounts for 26% of the variation in the per cent gamma globulin level up to 7 weeks of age. The estimates also indicated that a maternal affect was still present at 1 weeks of age. Heritability estimates, 1 .23, 1 .02, -0.47 and -0.54 for the periods hatch to 1, 1 to 3, 3 to 5 and 5 to 7 weeks of age respectively, on the index of gamma globulin change revealed that there was a significant genetic contribution to this trait in the early periods. Regression analyses showed that the 5 to 7 week period accounted for more of the variability in 1 week per cent gamma globulin level than any other period. The importance of the 5 to 7 week period was discussed as an indicator of the environmental influence on the per cent gamma globulin at this age period. No correlation was found between growth rate and the per cent gamma globulin level up to 7 weeks of age. / 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