1. The effects of antigen (Ag) injection on the distribution of lymphocyte populations of Cornell K‐strain male chickens were studied.
2. Two experiments were conducted. In the first, chickens were injected with Brucella abortus (BA), a purported T‐independent antigen. In the second, chickens were injected with sheep red blood cells (SRBC), a T‐dependent antigen. Peripheral blood lymphocytes (PBL) and spleen lymphocytes isolated at 0, 3, 6, 9, 12 and 24 h following Ag injection were stained with monoclonal antibodies (mAb) detecting B‐lymphocytes, CD4+ and CD8+ cells.
3. B‐lymphocytes in the blood or spleen showed no significant changes following either BA or SRBC injection. In contrast, CD4+ cells were decreased in the blood and increased in the spleen following BA and SRBC injections. CD8+ cells were decreased in both blood and spleen following BA injection but were unchanged in either blood or the spleen following SR8C injection.
4. These results indicate that there is a change in both spleen and circulating lymphocyte populations, especially T‐helper cells, following Ag injection. T‐helper cells are apparently the primary population involved in the initiation of humoral immunity. 相似文献
1. Growth, food intake, and food preference were measured in two experimental lines (White Rocks and White Leghorns) of chickens fed diets varying in content of lysine, methionine, or tryptophan. Diet A was balanced in all amino acids, while the remaining 6 diets were moderately ( ～ 30%) or slightly ( ～ 15%) deficient in either lysine, methionine, or tryptophan relative to NRC recommendations for broiler diets.
2. Body weight and food utilisation efficiency of White Leghorns at 10 d of age were not affected by diet, whereas the lower concentrations of lysine and methionine depressed these traits in White Rocks.
3. Tryptophan deficiency reduced food intake of White Leghorns, but not White Rocks.
4. With choice feeding of balanced and deficient diets from day 10 to 16, preferences between the diets were minimal for White Leghorns, whereas for White Rocks there was an almost immediate preference for the balanced diet, followed by lack of preference or preference for the deficient diet.
5. Apparently for some genetic stocks there is rapid adjustment to deficiencies in these amino acids with overconsumption, followed by compensation for preference of the balanced diet. The response, however, will vary depending on the deficient amino acid. 相似文献
1. Differences were found among eight populations of White Plymouth Rock pullets in the frequency of broken eggs.
2. The shells of such eggs were thinner than those of intact eggs in seven of the populations.
3. The number of defective eggs, the specific gravity of the eggs, and the percentage hen‐day egg production of normal eggs were significantly correlated within populations with the incidence of broken eggs.
4. No significant correlations were found within populations between the incidence of egg breakage and either egg weight, body weight, or shank length. 相似文献
Twenty-two Standardbred horses in race training were used in a crossover experiment to determine the effect of oral sodium bicarbonate (NaHCO3) administration on performance and metabolic responses to a 1.6-km (1-mile) race. Horses were paired and one horse in each pair was treated with either NaHCO3 (300 mg/kg BW) or a placebo, 2.5 h before they raced against each other. Each horse was scheduled to compete in two races, approximately 1 wk apart, one on each treatment. Horses always raced in the same pairs. Fourteen horses successfully completed both races. Jugular blood samples were obtained 1.5 h after treatment (rest), immediately before racing, 5 min post-race and 15 min post-race. In six horses, blood samples also were obtained 30 min post-race. Race times averaged 1.1 s faster after NaHCO3 treatment (P less than .1). Sodium bicarbonate treatment also elevated blood pH (P less than .05). In the horses sampled 15 and 30 min post-race, blood lactate disappearance was faster with the NaHCO3 treatment (P less than .05). The NaHCO3 may delay the fatigue precipitated by i.m. acidosis. Because other factors may limit performance (musculoskeletal soundness, cardiovascular and respiratory ability), NaHCO3 would not be expected to enhance the performance of all horses. However, the effect of NaHCO3 on lactate clearance may have implications for all intensively worked horses; because lactate and the associated hydrogen ions are believed to cause muscle damage and soreness, any mechanism to increase their removal rate could benefit the equine athlete. 相似文献
Chicks from lines selectively bred for either high or low antibody response post-primary immunization (PPI) to sheep erythrocytes (SRBC) and their reciprocal crosses were immunized intravenously with 0.1 ml of 0.25% SRBC antigen in Trials 1 and 3 and with 0.1 ml of 0.025%, 0.25%, or 25% SRBC antigen in Trial 2. All initial immunizations were made at 35 days of age, and 0.1 ml of 0.25% SRBC booster dose was given 24 days later. Results showed that (a) population differences appeared by day 4 PPI and persisted through day 24 PPI, (b) regardless of population, peak titers occurred at about the same time for primary and secondary immunizations, (c) dosage of antigen influenced differences among populations in antibody response to primary immunization, and (d) both selected lines had similar responses in 2-mercaptoethanol-sensitive and 2-mercaptoethanol-resistant antibodies to primary but not secondary immunization. 相似文献
Dramatic declines in the endangered Columbia Basin pygmy rabbit, a genetically unique population of small, burrowing rabbits in Northwestern United States, are likely the combined results of habitat degradation and fragmentation, disease, and predation. A critical component of pygmy rabbit habitat includes big sagebrush (Artemisia tridentata), which constitutes 82-99% of their winter diet and 10-50% of their summer diet. Sagebrush also forms the bulk of hiding cover around burrow sites. Across the range of pygmy rabbits, sagebrush habitat is grazed extensively by cattle. However, grazing has unknown effects on pygmy rabbits inhabiting the remaining, fragmented shrub-steppe habitat. We evaluated the effects of four grazing treatments on the distribution of pygmy rabbit burrows, diets of pygmy rabbits, and quality and quantity of vegetation at Sagebrush Flat in central Washington. Ungrazed areas contained significantly more burrows per unit area than did grazed areas. Vegetation composition and structure differed little among treatments in early summer before annual grazing by cattle. However, cattle grazing in late summer through winter removed about 50% of the grass cover, and reduced the nutritional quality (e.g., increased fiber and decreased protein) of the remaining grass. Although pygmy rabbits ate <2% grasses in winter, grasses and forbs comprised 53% of late summer diets. Because these endangered rabbits avoided grazed areas, removing cattle grazing from key habitat locations may benefit efforts to restore this rabbit in Washington. 相似文献
The objectives of this study were to compare glycerol and ethylene glycol at different concentrations as cryoprotectants and lycopene or cysteamine (with/without) as antioxidants in Tris extender for bull semen. Twenty‐four ejaculates were obtained from three bulls. Each ejaculate was split into four equal aliquots and diluted using both of the Tris extenders with glycerol (5% or 7%) or ethylene glycol (3% or 5%). After that, each extenders were split into three equal aliquots and added using both of the cysteamine 5 mm or lycopene 500 μg/ml, and control (without additives). The addition of 7% glycerol with cysteamine, 5% ethylene glycol with cysteamine and 3% ethylene glycol with cysteamine groups gave the lowest CASA motility than the other groups. However, 7% glycerol and 7% glycerol with lycopene resulted in a better rate of CASA progressive motility compared with that of other groups. Generally, all the lycopene groups signed better protective effects on acrosome and total morphology than the other groups. Glycerol 7% and 3% ethylene glycol with lycopene groups yielded to slight higher percentages of membrane integrity assessed by HOST than that of the other groups, but 7% glycerol with cysteamine and 3% ethylene glycol with cysteamine showed the worst percentages of membrane integrity. Glycerol 7% and 5% glycerol with lycopene gave rise to a higher value of VAP, VSL and VCL compared with that of the other groups. On the contrary, adding to 5% glycerol with cysteamine showed negative effect for VAP, VSL, VCL and ALH values. All cryoprotectant groups with lycopene decreased chromatin damage than the other groups. Ethylene glycol 3% led to lower non‐return rates of inseminated cows. However, this result was not considered to be statistically important. 相似文献
This paper provides baseline information on the involvement of women in small-scale coastal aquaculture such as the farming of slipper oyster, Crassostrea iredalei (Faustino 1933), and green mussel, Perna viridis (Linnaeus 1758). Data were gathered during a socio-economic survey of oyster and mussel farming in Western Visayas, Philippines conducted from July to December 1991.There were 175 respondents interviewed; 18.5% and 2.4% of oyster and mussel farmers were females. Fishing and related activities were the major source of livelihood for the majority of oyster and mussel farmers. In 1990, 79.4% and 69.8% of oyster and mussel farmers earned an annual income of less than P30 000 (1 USS P23). Based on the 1988 (latest data available) poverty threshold of P2654 (monthly) for Western Visayas, 80.4% and 71.7% of oyster and mussel farmers lived below poverty level in 1990. of 175 respondents. 79.3% and 48.2% of oyster and mussel farmers indicated that their household members participated in farming activities. More female household members were involved in oyster farming compared with mussel farming. Harvesting in mussel farming and both harvesting and marketing in oyster farming generated the widest participation among female household members. 相似文献
