A study, comprised of five parts, has been carried out on seven adult, female, pastel mink. Metabolic responses to ambient temperature have shown that these mink cannot tolerate temperatures much above 29°C, but are not unduly disturbed by low temperatures around 0°C. Under sleeping conditions, and within their thermal neutral zone (25 ±2°C) , the three animals measured did not demonstrate an abnormally high metabolic rate. Under conditions of prolonged fast, these mink appeared to maintain normal activity, although they lost much bodyweight. The apparently high, daily, urinary, nitrogen excretion, when related to heat production, gave a value of 2.5 mg of urinary nitrogen per Calorie (A.D.E.). The effect of additions of fibre to a basal ration has shown an inverse relationship between this component and the time of passage of the feed. The apparent digestibility of the ash component in the ration was markedly decreased with increasing increments of dietary fibre, but that of the fat was only very slightly reduced. Under these experimental conditions, nitrogen retention appears to be always positive, possibly reflecting a constant demand for fur growth, and a constant loss of nitrogen in the form of ammonia. Maintenance energy (A.D.E.) requirements of these mink have been quantitated. The effects of a decrease in cage capacity and the additions of fibre to the ration appear to decrease the animal's energy requirements. The Caloric intake of a one kg mink is almost identical to that suggested by the N.R.C. Water intake, when related to energy (A.D.E.), is appreciably less than the 1 gm / Calorie of heat produced generally accepted for mammals. However, it is in close agreement with figures obtained for the cat and for the mouse. The addition of a non-nutritive bulk to the ration significantly increases the water intake when related to the A.D.E. of the ration / Land and Food Systems, Faculty of / Graduate

The Fraser delta tidal marshes are important for migrating and wintering ducks, in particular, Mallard, Pintail, Widgeon, and Green-winged Teal. Agricultural, residential, and industrial development threaten the tidal marshes with destruction and quality loss. In order to preserve and protect the most valuable areas, and perhaps improve the characteristics which attract ducks, it was considered necessary to determine areas of most value, and the environmental characteristics which could be improved. A study of the occurrence and food habits of ducks on the tidal marshes was considered to be the best means of determining the importance of each unit. The relative importance of the tidal marshes for loafing and feeding habitat was indicated from a synthesis of all available information on duck use of the entire delta area. Aerial censuses conducted throughout two winters provided data on the distribution and abundance of Mallard, Pintail, Widgeon, and Green-winged Teal on the foreshore and adjacent upland. It was found that an annually variable population of ducks was present from September until May, with the largest numbers occurring during fall and spring migrations. The tidal marshes attracted approximately one-half the ducks on the deltas— with the largest proportions occurring in September, early October, late March, April, and May.. All four census units of the tidal marsh attracted similar winter totals of ducks although the relative number at each unit varied throughout the winter. As all of the tidal marshes appeared important to ducks, the features of all of them were studied. Area was determined from aerial photographs, and topographical relationships were determined from known tide levels. Composition and distribution of vegetation was determined from line transects. Relative production of seeds was determined from line transects and seed samples. The tidal marshes were found to cover approximately 3,733 acres, sloping from the approximately thirteen foot to the seven foot tide level. A six to eighteen inch "drop-off", which usually occurred near the ten foot tide level, separated the tidal marsh into an upper and lower zone, each with a different vegetative composition. Fourteen plant species were found, of which five Cyperaceae species, Scirpus americanus , Carex lyngbyei , Eleocharis macrostachya , Scirpus paludosus , and Scirpus validus composed ninety-three percent of all plants. The first two species, dominant on the lower and upper zones respectively, formed seventy percent of all plants. Distribution appears to be determined by the degree of tidal flooding, the degree of local drainage, and possibly by undemonstrated differences in soil and water salinity. Seed production varied annually, and was related to the degree of tidal flooding. Scirpus validus and Carex Lyngbyei produced the most seeds, followed next by Scirpus americanus. Ducks were collected on the tidal marshes and adjacent agricultural areas. Analysis of their stomach contents revealed that Carex Lyngbyei, Scirpus validus and Scirpus americanus were the most important- tidal marsh food items. Polygonum lapathifolium and P. persicaria were the most important seed foods taken on the agricultural areas. Although Mallard, Pintail, and Green-winged Teal consumed mostly seeds, Widgeon consumed primarily green vegetation, including winter rye, Lolium sp., and several Gramineae species. A synthesis of the available information indicates that the tidal marshes were most important as loafing areas from October until January, while during the remainder of the period, from September until May, they were also important for the provision of food. The control of water levels, by diking and pumping, appears to be essential for the improvement and protection of the tidal marshes. / Science, Faculty of / Zoology, Department of / Graduate

In order to investigate the nutritional requirements of ewes during late pregnancy and early lactation, two groups of ewes were given 90 gms. Digestible Crude Protein (D.C.P.) during pregnancy and 225 gms. D.C.P./head/day during early lactation. During the last six weeks of pregnancy ewes in Group II, provided with maintenance + 100%, requirement of Digestible Energy (D.E.) made significantly greater liveweight gains (P<0.01) than those in Group I and fed maintenance + 50%, D.E. During early lactation ewes in Group I, provided with maintenance + 150%, D.E. lost significantly less weight (P<0.05) than those in Group II which were given maintenance + 100%, D.E. There were no significant differences in milk yield and milk composition between the two groups, however pre-weaning lamb growth in Group I was significantly greater (P<0.05) than that in Group II. Average daily gain of weaned lambs (weaned at 8 to 10 weeks of age) given pelleted rations containing 20%, protein was significantly greater (P<0.05) than those given 16%, protein but there were no significant differences between lambs fed 20% or 13% and between 16%, or 13%, crude protein. A higher proportion of single lambs in the group given 13% protein may have accounted in part for the better gain of this group. Results of the digestion trial with these lambs indicated that there were no significant differences (P<0.05) in the dry matter digestibility and the protein digestion coefficient of the three types of pellets but the nitrogen retention was greatest in the lambs fed the 20%, protein. The results of the second experiment conducted, to study the effect of non-protein nitrogen in the form of urea on milk yield and milk composition of ewes indicated that there were no significant differences in milk yield, milk composition and milk urea N level of the three groups of ewes fed equal amounts of supplemental nitrogen, during early lactation, as soybean, soybean + urea and urea alone. Ewes fed soybean or soybean + urea had significantly lower plasma urea nitrogen levels (P<0.05) than those supplemented with urea alone. There was no significant difference between the plasma urea nitrogen level of the former two groups of ewes. There were no significant differences in the pre-weaning growth of lambs nursing ewes fed on pellets containing soybean + urea and urea alone but the lambs from ewes fed soybean made significantly slower (P<0.05) gain than those from the other two groups. .The reason for this slower rate of gain is difficult to explain. Results of the trial conducted to investigate the use of urea nitrogen in early weaned lambs indicated that the lambs fed on pellets containing soybean made significantly greater gains (P<0.05) than those on pellets containing urea as the sole source of supplemental nitrogen. There were however, no significant differences in weight gain of lambs fed on pellets containing soybean or soybean + urea and between soybean + urea or urea alone. There were no significant differences between plasma urea nitrogen level of lambs fed on soybean or soybean + urea containing pellets and these lambs had significantly higher (P<0.05) levels of plasma urea nitrogen than those fed on pellets containing urea alone. The variation in the blood urea level of the lambs was thought to be due to variation in protein intake. Results of the digestion trial with lambs showed that there were no significant differences in the protein digestion coefficients and dry matter digestibilities of these types of rations. Pellets providing nitrogen from soybean resulted in greatest nitrogen retention. Results show that urea did not influence the milk yield or milk composition of the ewes but it was a poor source of nitrogen for early weaned lambs. / 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

New sugar beet varieties may qualify as an advanced biofuel feedstock in the U.S., but new alternatives to conventional pile storage are necessary to preserve fermentable sugars and allow yearlong beet ethanol production. Fermentable sugar preservation was assessed in sugar beets stored under aerobic and anaerobic atmospheres and in raw thick juice stored at acidic (2&le; pH&le; 5) and alkaline (8&le; pH&le;11) conditions. Aerobic storage of sugar beets at 4&deg;C for 14 wk resulted in higher fermentable sugar retention (99&plusmn; 4%) than at 25&deg;C or anaerobic storage at 4&deg; C and 25&deg; C. Raw thick juice retained &ge; 99% of fermentable sugars at pH 3.5 and 9.5 and refractometric dissolved solids content of 64.5&deg; Bx. The changes in fermentable sugars in raw thick juice stored for 24 wk at acidic and alkaline pH were modeled by response surface methodology. Although raw thick juice was stored successfully at acidic and alkaline pH, conditions for high-efficiency fermentation must be developed.