Three studies were designed to evaluate the promoting effect of cyclopropenoid fatty acids (CPFA) on avian myeloblastosis virus (AMV) infection in White Leghorn chickens. In the first study effects on growth parameters, blood serum and erythrocyte lipid composition of White Leghorn chickens were investigated at 100 ppm and 300 ppm dietary CPFA. In comparison to controls, chicks fed dietary CPFA had reduced body weights and food intake. At both levels, CPFA increased the saturated fatty acids and decreased monoenes in blood serum and erythrocyte triacylglycerols and phospholipids. In a second study, the effects of high dietary (300 ppm) CPFA on AMV infectivity were investigated. Chicks were inoculated with 0.1 ml AMV at 7 days of age. A diet containing CPFA was fed before and after inoculation. CPFA/AMV treated chicks showed a marked reduction in body weight gain and food consumption in comparison to controls. CPFA appeared to promote AMV infection along with unexpected violent hemorrhagic manifestations. These hemorrhagic manifestations appeared to cause death before AMV induced myeloblast proliferation in the circulating blood. In comparison to controls, CPFA altered the phospholipid composition of isolated myeloblasts and the cholesterol/phospholipid ratio of isolated myelobasts, myeloblast plasma membrane, and virus particles. Analysis of the acyl group composition of choline and ethanolamine phospholipids from CPFA treated myeloblasts and myeloblast plasma membrane revealed an increase in saturated fatty acid and a decrease in monoenes. In both, CPFA appeared to affect ethanolamine more than choline phospholipids. In contrast, the alterations observed in CPFA treated virus particle choline and ethanolamine fatty acyl chains were reversed from those found in the myeloblast and myeloblast plasma membrane. In addition, ATPase specific activity was altered in relation to the CPFA induced lipid changes in the myeloblast plasma membrane and virus particle. It was shown that as saturation increased enzyme activity increased. As a third investigation, the effects of low dietary (75 ppm and 150 ppm) CPFA on AMV infection was conducted in an attempt to eliminate the hemorrhagic manifestations. A difference that was observed between this investigation and the 300 ppm CPFA/AMV study was less severe hemorrhagic responses. Histological examination of CPFA treated liver and spleen by light microscopy revealed heavy infiltration of mitotic myeloblasts into each tissue. Analysis of the number of virus particle/ml by reverse transcriptase revealed 300 ppm dietary CPFA stimulated the synthesis and release of virus particles. This was in contrast with 150 ppm dietary CPFA which retarded the synthesis and release of virus particles. / Graduation date: 1982

Six experiments were carried out with Single Comb White Leghorn laying chickens to assess the effect of feeding a source of direct-fed microbials (Lactobacillus; Lacto) and its carrier [condensed cane molasses solubles (CCMS)] on the retentions of fat, nitrogen and several minerals; on the status of the pH of the gastrointestinal (GI) tract; on the phytase activities in the Lacto and in the crop and in the intestinal contents and intestinal, pancreatic and liver tissues; on the histological and anatomical changes of the GI tract and on the production performance. Feeding 1,100 mg Lacto/kg diet (ppm) and 2,200 ppm Lacto in corn-soya bean meal (C-S) diets to layers stimulated appetite, improved egg production (in Experiment 1 only), egg mass, egg weight, egg size, internal egg quality and fat, nitrogen, calcium and phosphorus retentions (P < .05). Production performances were not different between the layers fed the 1,100 ppm diet and those fed the 2,200 ppm Lacto diet. Supplementing Lacto diets with 1 and 3% fat reduced feed consumption, provided better feed conversion, egg production, egg masses, egg size, body weight gains, and nitrogen, calcium and phosphorus retentions. Feeding 1,100 ppm Lacto barley-corn-soya bean (B-C-S) layer diets improved body weight gains and the retentions of fat, phosphorus and manganese and increased the rate of passage of digesta (P < .05). Feeding Lacto C-S and Lacto B-C-S layer diets increased cellularity of Peyer's patches in the ileums of the layers which may stimulate the mucosal immune system. No changes in length and weight of the intestine were observed. Daily feed consumption and body weight gains were improved when pullets were fed 1,100 ppm Lacto from 7 to 19 wk of age (WOA). When these pullets were continued on the Lacto feed during the laying period (20 to 59 WOA), increased feed consumption, egg size, nitrogen and calcium retentions, increased cellularity of Peyer's patches, decreased length and weight of intestine were observed (P < .05). Presence of phytase activity was higher in condensed cane molasses solubles (CCMS)- Lactobacillus premix than the carrier (CCMS). Feeding the CCMS-Lacto diets to layers decreased the pH of the GI tract, increased phytase activities in the GI tract and intestinal tissues and improved shell thickness and phosphorus retention (P < .05). The production performance of layers fed .45% and .25% available phosphorus (AP) diets were not different except for body weight gain. Phosphorus retention was better for layers fed diets containing .25% AP with CCMS-Lacto than the .45% AP control diet. According to these studies, feeding Lacto to pullets and layers improved their performance and the retention of nutrients such as calcium, phosphorus and nitrogen which subsequently reduced the cost of feeding. / Graduation date: 1994

Experiments were conducted to evaluate nitric oxide (NO) involvement in the leptin effect on food intake in both broiler and Leghorn chickens. The first experiment studied the effect of leptin combined with L-arginine on the food intake in broilers. Intracerebroventricular (ICV) administration of human recombinant leptin injection decreased (P=.01) food intake from 15 to 150 minutes compared to the control group treated with artificial cerebrospinal fluid ( aCSF) while food intake was increased by L-arginine. Food intake between the group receiving leptin and L-arginine was similar to the control group. Therefore, broilers were sensitive to the anoregenic effects of leptin, while L-arginine, a NO precursor appeared to attenuate the leptin effect on food intake. The effect of leptin and L-NNA on food intake in broilers was measured in the second experiment. Lepin, L-NNA and leptin plus L-NNA decreased food intake. The NO inhibitor L-NNA tended to enhance the suppression of leptin on food intake. In the third experiment, using Leghorns instead of broilers, the ICV injection of leptin decreased food intake from 15 to 60 minutes postinjection (P=.05). However, food intake was not affected by injection of L-arginine plus leptin. Therefore, L-arginine appeared to antagonize the leptin inhibitory effect on food intake. A small increase food intake induced by L-arginine was also observed (P=.09). The change of food intake in Leghorns administered leptin and L-NNA were measured in Experiment 4. Food intake was decreased by L-NNA and leptin with the effects lasting 60 minutes, similar to that observed in broilers (P<0.0l). For group B (leptin treatment), there was decreased food intake within 45 minutes (P=.04) and the effect disappeared 60 minutes, post injection. Also, the results along with Experiment 2 demonstrated that NO mediated the effect of leptin in Leghorns. The fifth experiment investigated the change in concentration of metabolites of nitric oxide after injection of leptin within 30 minutes. The group treated with the leptin had a lower level of metabolites of nitric oxide in the hypothalamus than the control group (P=.004). This effect further demonstrates that leptin modulated feeding activity through its inhibition on nNOS activity in the hypothalamus. These results showed that both leptin and NO participated in the regulation of food intake in broiler and Leghorn chickens, and the effect of hypothalamic neuropeptidergic circuitry leptin on food intake was mediated by NO. / Master of Science

24 pairs of newly-hatched Leghorn chicks were randomly divided into 3 groups. Ss in one group followed a moving object for 30 min on Day 1 of life; Ss in another group followed for 30 min on Day 2; Ss in the remaining group followed for 15 min on Day 1 and 15 min on Day 2. One S in each pair followed by his own effort, while the other S rode behind the object in a transparent box. On Day 4, Ss were tested for the duration of following of the object. No important differences among groups were observed. On Day 6, Ss were tested for ability to discriminate between the original and a novel object, and for following the original. Active Ss scored significantly higher than passive Ss on all Day 6 tests; Ss trained on Day 2 scored significantly higher on the following than Ss trained on Day 1. The results suggest that the ‘law of effort’ may apply more to discrimination than to recognition of the imprinting object.