Manipulation of plasma uric acid in broiler chicks and its effect on leukocyte oxidative activity

Birds have high metabolic rates, body temperatures, and plasma glucose concentrations yet physiologically age at a rate slower than comparably sized mammals. These studies were designed to test the hypothesis that the antioxidant uric acid protects birds against oxidative stress. Mixed sex broiler chicks (3 wk old) were fed diets supplemented or not with purines (0.6 mol hypoxanthine or inosine). Study 1 consisted of 18 female Cobb x Cobb broilers that were fed purines for 7 days, whereas study 2 consisted of 12 males in a 21-day trial. Study 3 involved 30 mixed sex broilers that were fed 40 or 50 mg allopurinol/kg body mass (BM) for 21 days, a drug that lowers plasma uric acid (PUA). PUA and leukocyte oxidative activity (LOA) were determined weekly for all studies. For study 2, pectoralis major shear force, relative kidney and liver sizes (RKS and RLS), and plasma glucose concentrations were also determined. In study 1, PUA concentration was increased three- and twofold (P < 0.001) in birds fed inosine or hypoxanthine, respectively, compared with control birds. LOA of birds supplemented with inosine was lower (P < 0.05) than that of control or hypoxanthine birds. In study 2, PUA concentrations were increased fivefold (P < 0.001) in birds fed inosine and twofold (P < 0.001) in birds fed hypoxanthine compared with control birds at day 21. RKS (g/kg BM) was greater (P < 0.001) for chicks fed purine diets compared with control chicks. Muscle shear value was lower (P < 0.05) in chicks fed purine diets. PUA concentration was decreased (P < 0.001) in birds consuming allopurinol diets, whereas LOA was increased (P < 0.01) in study 3. These studies show that PUA concentrations can be related to oxidative stress in birds, which can be linked to tissue aging.     

The utilization of torula yeast in diets for White Leghorn birds during growth and laying periods

A total of 1440 one-day-old female White Leghorn birds was used in a 2 × 4 × 2 factorial experiment to evaluate the inclusion of torula yeast (grown on sugar cane final molasses) in grower diets for 0–6 weeks of age (0 and 20%), for 7–23 weeks (0, 6, 12 and 17%) and in laying hens' diets (0 and 18%). In the period 0–6 weeks of age, final live weight and feed conversion (465 and 444 g and 2.70 and 2.82) obtained with 0 and 20%, respectively, differed significantly (P < 0.05) but this had no effect on the later performance of the birds. For 7–19 weeks of age, average live weight gain (1143, 1119, 1093 and 1021 g/bird) was reduced by increasing the percentage of torula yeast in the diet, but conversion (4.43, 4.47, 4.48 and 4.72) increased significantly only with 17% torula. Torula yeast levels used for weeks 7–23 had no influence on subsequent egg production. The inclusion of 18% yeast during the laying period did not affect egg production (250 and 247 eggs/bird/year) nor egg weight (58.4 and 58.1 g) but increased consumption from 37.4 to 38.8 kg/bird/year. The results obtained suggest the possibility of including 20%, 17% and 18% torula yeast in diets for White Leghorn birds for weeks 0–6, weeks 7–23 and for laying hens, respectively.     

The effect of vasotocin on plasma glucose, free fatty acids and growth hormone in the frog, Rana catesbeiana

Injections of arginine vasotocin into bullfrogs had no effect on plasma glucose after 30 min. but caused hyperplycemia after 120 min. Plasma levels of growth hormone were elevated earlier (30 min.) and returned to control levels after 120 min. Plasma free fatty acids were unaltered following vasotocin administration. It is suggested that the hyperglycemic effect of vasotocin may be mediated via growth hormone.     

Genome‐wide association study reveals novel variants for growth and egg traits in Dongxiang blue‐shelled and White Leghorn chickens

This study was designed to investigate the genetic basis of growth and egg traits in Dongxiang blue‐shelled chickens and White Leghorn chickens. In this study, we employed a reduced representation sequencing approach called genotyping by genome reducing and sequencing to detect genome‐wide SNPs in 252 Dongxiang blue‐shelled chickens and 252 White Leghorn chickens. The Dongxiang blue‐shelled chicken breed has many specific traits and is characterized by blue‐shelled eggs, black plumage, black skin, black bone and black organs. The White Leghorn chicken is an egg‐type breed with high productivity. As multibreed genome‐wide association studies (GWASs) can improve precision due to less linkage disequilibrium across breeds, a multibreed GWAS was performed with 156 575 SNPs to identify the associated variants underlying growth and egg traits within the two chicken breeds. The analysis revealed 32 SNPs exhibiting a significant genome‐wide association with growth and egg traits. Some of the significant SNPs are located in genes that are known to impact growth and egg traits, but nearly half of the significant SNPs are located in genes with unclear functions in chickens. To our knowledge, this is the first multibreed genome‐wide report for the genetics of growth and egg traits in the Dongxiang blue‐shelled and White Leghorn chickens.     

食物温度对大鼠体重、血糖、血脂及抗氧化作用的影响

目的：观察食物温度对大鼠体重、血糖、血脂及抗氧化作用的影响。方法：将40只Wistar大鼠随机分为4组（A组、B组、C组、D组）,分别喂食不同温度（10～15℃、22～32℃、42～52℃、52～62℃）的食物和饮水,饲养35d后测量体重,测定血糖（G）、总胆固醇（TC）、甘油三脂（TG）,测定血清中超氧化物歧化酶（SOD）活性、谷光甘肽过氧化物酶（GSH-Px）活力及丙二醛（MDA）和蛋白含量。结果：采用不同温度的饮食喂养35d后,各组大鼠的体重、血糖、血脂无显著差异（P〉0．05）;C组大鼠的血浆SOD和GSH-Px活性明显高于A组（P〈0．05）,MDA和蛋白含量显著低于A组（P〈0．05）。结论：不同温度的饮食对代谢的影响不明显．42～52℃饮食组大鼠的生化指标较为稳定,有较强的抗氧化作用,过低温度的饮食使机体处于应急状态。     

Mapping quantitative trait loci for egg production traits in an F2 intercross of Oh-Shamo and White Leghorn chickens

We performed quantitative trait locus (QTL) analyses for egg production traits, including age at first egg (AFE) and egg production rates (EPR) measured every 4 weeks from 22 to 62 weeks of hen age, in a population of 421 F₂ hens derived from an intercross between the Oh‐Shamo (Japanese Large Game) and White Leghorn breeds of chickens. Simple interval mapping revealed a main‐effect QTL for AFE on chromosome 1 and four main‐effect QTL for EPR on chromosomes 1 and 11 (three on chromosome 1 and one on chromosome 11) at the genome‐wide 5% levels. Among the three EPR QTL on chromosome 1, two were identified at the early stage of egg laying (26–34 weeks of hen age) and the remaining one was discovered at the late stage (54–58 weeks). The alleles at the two EPR QTL derived from the Oh‐Shamo breed unexpectedly increased the trait values, irrespective of the Oh‐Shamo being inferior to the White Leghorn in the trait. This suggests that the Oh‐Shamo, one of the indigenous Japanese breeds, is an untapped resource that is important for further improvement of current elite commercial laying chickens. In addition, six epistatic QTL were identified on chromosomes 2, 4, 7, 8, 17 and 19, where none of the above main‐effect QTL were located. This is the first example of detection of epistatic QTL affecting egg production traits. The main and epistatic QTL identified accounted for 4–8% of the phenotypic variance. The total contribution of all QTL detected for each trait to the phenotypic and genetic variances ranged from 4.1% to 16.9% and from 11.5% to 58.5%, respectively.     

The effect of incubation temperature, sodium chloride and ascorbic acid on the growth kinetics of Aeromonas hydrophila

The effects of temperature, sodium chloride and ascorbic acid on the aerobic growth kinetics of a clinical strain of Aeromonas hydrophila were evaluated. At 5°C, ascorbic acid (1 mmol l^-1) and sodium chloride (3% w/v) inhibited the growth of the organism. At 10°C, ascorbic acid depressed only the maximum population densities (A) by approximately 2 log cycles, but not maximum specific growth rate (μ_m) or the lag time (Λ). On the contrary, NaCl caused A to increase, with the effect being greatest when the NaCl content was 1.5%. Temperature increase from 10 to 15°C resulted in an approximate doubling of μ_m and unexpectedly an apparent increase in Λ However, this apparent increase resulted from the particular manner in which the lag phase was mathematically calculated.     

Transport of p-aminohippuric acid, uric acid and glucose in highly purified rabbit renal brush border membranes.

A procedure for preparing highly purified brush border membranes from rabbit kidney cortex using differential and density gradient centrifugation is described. Brush border membranes prepared by this procedure were substantially free of basal-lateral membranes, mitochondria, endoplasmic reticulum and nuclear material as evidenced by an enrichment factor of less than 0.3 for (Na+ + K+)-ATPase, succinate dehydrogenase, NADPH-cytochrome c reductase and DNA. Alkaline phosphatase was enriched ten fold indicating that the membranes were enriched at least 30 fold with respect to other cellular organelles. The yield of brush border membranes was 20%. Transport of D-glucose by the membranes was identical to that previously reported except that the Arrhenius plot for temperature dependence of transport was curvilinear (EA = 11.3--37.6 kcal/mol) rather than biphasic. Transport of p-aminohippuric acid and uric acid were increased by the presence of NaCl, either gradient or preequilibrated. However, no overshoot was obtained in the presence of a NaCl gradient, and KCl and LiCl also produced equivalent stimulation of transport suggesting a nonspecific ionic strength effect. Uptakes of p-aminohippuric acid and uric acid were not saturable, and were increased markedly by reducing the pH from 7.5 to 5.6. Probenecid (1 mM) reduced p-aminohippuric acid and uric acid (50 muM) uptake by 49% and 21%, respectively. We conclude that the uptake of uric acid and p-aminohippuric acid by renal brush border membranes of the rabbit occurs primarily by a simple solubility-diffusion mechanism.     

The effect of fodder plant genotype on the variation of larval fitness traits in genotype classes of green oak leafroller moth

The effect of genetic variation of oak (Quercus pubescens L. and Q. petraea L.) on the genotype fitness components in green oak leafroller moth larvae (Tortrix viridana L.) at esterase (Est-4) and protease (Pts-4) loci was studied. The samples of larvae were collected from nine oak trees, whose genetic variation was assayed by RAPD-PCR using primer OPA14. The contributions of the factors of oak species/genotype and green oak leafroller moth genotype and their interaction to the variation of important size-related traits of the larvae were evaluated by two-way ANOVA. It was shown that the same larval genotype can display maximum fitness on the trees of one species or genotype and minimum, on the trees of other species or genotype. The interactions between the oak genotype and green oak leafroller moth genotype factors lead to the relationships that appear in statistically significant associations between genotype classes of green oak leafroller moth and oak. These results are discussed from the standpoint of a recently developed new field, community or ecosystem genetics.