Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 85-94). Also available on the Internet.

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Experiments were designed to investigate the possibility of using mice as model animals for the evaluation of protein quality, and to compare it with rats under the same conditions. Parameters measured were protein efficiency ratio, net protein ratio, protein digestion and relative protein value. Six sources of protein were tested at three dietary levels for each. Measurements were taken at four different periods of feeding, thus, the effects of dietary level of protein and the length of the feeding period were studied. Results on mouse experiment indicated that the highest PER values were obtained at 6 and 8% levels of dietary protein with significantly lower values when 11% levels were fed. The highest NPR values were obtained at 6% level of dietary protein then declined when 8 or 11% levels were fed. The highest efficiency regarding PER and NPR were obtained when mice were fed for 10 days than when they were fed for 14, 21, or 28 days of experiment. High quality protein sources were needed at lower levels in the diet for shorter periods of time to obtain the maximum efficiency when compared to poor quality sources of protein. Results for protein digestion did not correlate with those of PER, NPR or RPV indicating that protein digestion is a poor measurement. However, PER, NPR, and RPV were highly correlated. Results of rat experiment were in agreement with what was reported in the numerous works for rat bioassay in the literature review. Rate of body weight gain increased with increasing levels of dietary protein and the PER reached a maximum value, then decreased. Values of NPR tended to fall with increasing levels of dietary protein. PER values tended to increase gradually with prolonged period of feeding, then decline. The maximum PER values were obtained when 10% level of dietary protein was fed for a period of 15 days. Likewise mice experiment, PER, NPR, and RPV correlated highly while protein digestion correlated poorly with the other methods used. In general mice appeared to be influenced by the same factors as rats when used for the evaluation of protein quality. Mouse could be used as a model animal for protein quality evaluation with the advantages of small animal size, lower feed intake, shorter period of feeding, plus is highly desirable for experiments involving the use of isotopes or whole carcass analysis. A dietary protein level of 8% for a feeding period of 10 days would be suitable for use with mice instead of a 10% dietary level for a 28 day feeding experiment in rats. Whole eggs could be used as a suitable reference standard protein for mouse bioassay.

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Two experiments were conducted to evaluate the effects of arginine, vitamin E, and their combination on cardiopulmonary performance and nitric oxide synthase (NOS) activity in broilers undergoing cold-induced ascites (pulmonary hypertension) after an acute challenge with epinephrine. One day-old male broilers ( n = 25/treatment) were supplemented with arginine (0.3% water supplementation), vitamin E (400 IU/L or kg, water or feed supplementation; experiment 1 and 2 respectively) or both compounds, above NRC (1994) recommendations. From day 28 to 42, a catheterization was performed (n = 8/treatment) to evaluate pulmonary and mean arterial pressures, and heart rate. After recording baseline values, two injections of epinephrine (1 or 0.5 mg/kg body weight, experiment 1 and 2, respectively) were administered in a 20 min interval. The NOS activity was estimated through the conversion of 14C-arginine to 14C-citrulline in isolated pulmonary arteries ( n = 8/treatment). Overall, the time taken for pulmonary arterial pressure to return to values no different from initial baseline levels was longer for the birds consuming high levels of vitamin E (alone or in combination with arginine) compared to birds supplemented only with arginine. Although NOS activity was highly variable, birds fed with high arginine levels tended to have the lowest NOS activity. These results showed that vitamin E supplementation at the levels used in these experiments has detrimental effects on cardiopulmonary performance, and does not improve NOS activity in isolated pulmonary arteries.

Experiments were conducted to investigate the effects of dietary fat, vitamin E(Vit. E) and selenium(Se) supplementation on the performance, fatty acid(FA) composition, lipid oxidation on blood and the oxidative stability of muscle tissues (breast and thigh) during refrigerated storage of broiler chickens fed high levels of flaxseed(FXS). Four hundred and eighty d-old broiler chicks were fed experimental diets for a 3 wk period, which consisted of the combination of two dietary fat sources: fullfat soybean(FFSB) and FXS; 3 Vit. E levels: 10, 40 and 80 IU/kg and two Se levels: 0.15 and 0.30ppm (Exp. I). Four hundred and forty d-old chicks were fed on FFSB diets supplemented with 10, 80, and 160 IU of Vit. E/kg, FXS diets supplemented with 10, 40, 80, 120, 160 and 200 IU of Vit. E/kg, corn-soybean based diet (control), and on a commercial diet for 21 days (Exp. II). For Exp. III, 1680 (840 of each sex) d-old broiler chicks were raised up to 41d. Three basal diets containing 10% FXS and 3 levels of Vit. E: 60-, 90- and 160 IU/kg were formulated for 3 age periods: starter (0--3wk), grower (3--5 wk) and finisher (5--6wk). Three groups of birds were fed these basal diets, while 3 other groups were fed the diet containing 160 IU of Vit. E either during the starter, grower or finisher phase (diets supplemented with 60 IU/kg were given in the two remaining phases). (Abstract shortened by UMI.)

The present study was performed to determine if pigs varying in their susceptibility to stress, adapted to a casein-based diet, experience an improvement in biochemical parameters related to stress and behaviour compared to pigs adapted to the traditional western canadian cereal-based swine diet. Experiment 1 involved separating fifty-eight, 8-week old pigs according to genotype with respect to the halothane gene. Within each genotype pigs were divided into 2 groups and assigned to either a control diet or to a diet where most of the protein source was substituted for casein. All animals were adapted to diet for 6 weeks and experienced a weekly blood sampling stressor. Day 1, 14 and 35 of the plasma samples were analyzed for glucose, cortisol, ACTH, insulin, pyridoxal 5$ sp prime$-phosphate (PLP), amino acid concentrations and dopamine-$ beta$-hydroxylase (DBH) activity; metabolic indices known to be responsive to stress. Experiment 2 involved separating fifty-seven, 14-week old pigs in the same manner, then adapting the pigs to their respective diets for a period of 4 weeks. Afterwards, pigs were transferred from their pen to a novel pen-maze situation where they had their behaviour monitored for a period of one hour. Results of these experiments have revealed that (1) the stress susceptible and carrier pigs experienced reduced day 35 plasma glucose, PLP concentrations and DBH activity compared to normal pigs; (2) dietary adaptation to the casein diet resulted in greater day 14 and 35 PLP levels and day 35 essential amino acid lysine, threonine, methionine, tryptophan and arginine concentrations compared to control-adapted pigs; (3) the carrier pigs investigated their surroundings more frequently than the stress susceptible pigs, and the normal pigs engaged in the through-maze behaviour more often than the stress susceptible pigs; and (4) adaptation to the casein diet, compared to the control diet, resulted in fewer displacement-type behaviours such as drinking

Various aspects of the ascorbic acid (vitamin C) nutrition of Oreochromis niloticus and O. mossambicus are considered in this treatise. The activity of L-gulono-Y-lactone oxidase was assessed in liver and kidney of 14 teleosts of 3 genera, histochemically (qualitatively) and biochemically (quantitatively). Activity of this enzyme was only detected in liver and kidney of common carp, Cyprinus carpio, and kidney of O. spilurus and O. aureus. No activity was detected in the species considered herein. The quantitative dietary ascorbic acid requirements of juvenile O. niloticus and O. mossambicus were determined by feeding diets containing graded levels of the vitamin (O~400mg/lOOg) and were based on growth response, food utilization, gross body composition data, tissue and biochemical changes and ability to prevent signs of ascorbic acid deficiency. The recommended level of supplementation of dietary ascorbic acid is l2Smg/lOOg and the net requirement 42mg/lOOg diet. Long-term ascorbic acid deprivation in £. niloticus and O. mossambicus resulted in poor performance in terms of growth, food utilization and survival. Other parameters evaluated included hepatosomatic index, liver and muscle glycogen content, blood parameters, tissue ascorbate concentrations, collagen contents, hydroxyproline and proline contents, and serum transaminase and cholesterol levels. Signs of ascorbic acid deficiency were severe and included haemorrhage~ opercular deformity, tail erosion, exophthalmia, cataract and spinal deformity (lordosis and scoliosis). Histologically scorbutic fish showed evidence of generalized bone changes associated with excessive production of chondrocytes and failur~ of ossification of growing bone areas. Eye lesions were associated with scleral collapse and also observed was hyperplasia of gill secondary lamellae epithelial cells and pronounced steatitis. Tissue ascorbate concentrations were correlated with dietary ascorbic acid levels and both species exhibited highest concentrations in the ovary, brain and testis, followed by heart, liver, gut, gills, eyes and the lowest levels in muscle and gall-bladder. The physiological role for ascorbic acid in each tissue is discussed. Eight week growth studies were conducted to evaluate the utilization of L-ascorbic acid (AA), the sodium salt of L-ascorbic acid (NaAA), glyceride coated L-ascorbic acid (GCAA), the barium salt of L-ascorbic acid 2-sulphate (AA2S) and ascorbyl palmitate CAP) in diets for O. niloticus and O. mossambicus, All five forms were added to the basal diet, containing no ascorbic acid CAAF), on an equimolar basis to supply 12Smg ascorbic acid/IOOg diet. All forms performed well in terms of growth, food utilization, and prevented signs of deficiency, Retention of ascorbic acid in diets after processing was increased by increasing dietary ascorbic acid level. AA2S and GCAA were more stable than AA and NaAA during processing and storage. The stability of AA, NaAA, GCAA and AA2S under different storage conditions was in descending order as follows: Freezer (_20°C), Fridge (S-BoC), room temperature in black bags (22-24°C) and room temperature in clear bags (22-24°C). Leaching of dietary ascorbic acid increased with increasing immersion time and water temperature. Stability and price of each form evaluated suggested that GCAA is to be preferred for use in fish feeds. The antioxidant effects of ascorbic acid were investigated. The results showed that ascorbic acid was not as effective as butylated hydroxy toluene (BHT) in preventing in vitro oxidation. An experiment was conducted to compare the performance of a commercial trout diet with the same diet supplemented to a level of l2Smg ascorbic acid/lOOg diet (Diet 2) when fed to O. niloticus. Fish fed the supplemented diet performed significantly better in terms of growth and food utilization concomittant with significantly increased tissue ascorbate concentrations. Sex differences in relation to dietary ascorbic acid nutrition were investigated. Females of both species exhibited significantly higher gonado~ and hepatosomatic indices than males. Females in both species eXhibited higher total ascorbate concentrations in gonad, gills, spleen, brain and blood than males whereas the reverse was true for the eyes. Dehydroascorbic acid (DHAA) levels were very low in tissues of both species. Ascorbic acid depleted O. niloticus fingerlings were fed on each of three diets providing nil, adequate Cl2Smg ascorbic acid/lOOg diet), and luxus (400mg/lOOg diet) of the vitamin after small surgical incisions had been made in dorsolateral musclature. Fish from each group were sampled regularly over 16 days and histological evaluation of the lesion area carried out as well as measurement of the tissue ascorbate levels. Epithelial elements of the healing process developed irrespective of the vitamin level but although fibroblast activity was marked in all three groups, collagenisation was very much slower in the deficient group, and in these the lesion was not mature, even at the termination of the experiment. The role of ascorbic acid in reproduction of tilapias was investigated in three experiments. The first showed that ascorbic acid supplementation of broodstock feed improved both hatchability and fry condition. In the second experiment fry produced from fish fed an unsupplemented diet and subsequently fed the same diet performed poorly in respect of growth and food utilization. Fry produced from broodstock fed the supplemented diet and subsequently fed the unsupplemented diet performed better than the previous group. This indicates transfer of ascorbic acid from the ovary to the eggs thence to the fry providing some protection against ascorbic acid deficiency during the early stages of life.

Dietary fats have been proposed to alter the amount of glucose transporters in various tissues. This study examined how diets containing linoleic or palmitic fatty acids affected the amount of the major insulin-responsive glucose transporter protein, GLUT-4, in red vastus muscle of mice. At 8 weeks of age, 28 healthy female mice were separated into 3 dietary groups, one control group (5% corn oil fat) and two high fat (15% fat) groups. One of the high fat diets was a linoleic acid rich diet (76% linoleic polyunsaturated fat), while the other was a palmitic acid rich diet (95% palmitic saturated fat). The mice remained on their respective diets for 12-13 weeks until sacrifice. Red vastus muscle samples were removed and prepared for GLUT-4 protein analysis. Homogenized red vastus muscle samples were separated by SDSPAGE, transfered to membrane paper, and immunoblotted. scanning densitometry determined the relative quantity of GLUT-4 from each sample. TAP GLUT-4 protein in the group fed the linoleic acid rich diet was 9% higher than the group fed the low fat diet, and 37% higher than the group fed the palmitic acid rich diet. These data suggest that a prolonged high fat diet consisting of linoleic or palmitic fatty acids play a role in the regulation of GLUT-4 protein content. / School of Physical Education