The influence of crate height on selected biochemical indices in captive‐reared mallards

The aim of this study was to investigate the effects of crate type (particularly its height) on selected biochemical indices in captive‐reared mallards (Anas platyrhynchos). The physiological changes in response to 2‐h crating in crates of either 20 cm or 26 cm height were monitored in 6‐week‐old mallards. Plasma corticosterone concentrations showed an increase (P = 0.036) in mallards crated in crates of 26 cm height in comparison with control non‐crated birds, whereas no difference in plasma corticosterone levels was found between mallards crated in crates of 20 cm height and control non‐crated birds. Lower concentrations of plasma triglycerides (P < 0.05) and uric acid (P < 0.05) were found in crated mallards in comparison with control non‐crated birds; the height of the crates had no effect. Mallards crated in crates of 26 cm height also exhibited a higher (P = 0.032) plasma lactate dehydrogenase concentration in comparison with control non‐crated birds, whereas no difference (P > 0.05) was found in lactate dehydrogenase concentrations in mallards crated in crates of 20 cm height. Our results suggest that crating mallards in lower crates (20 cm) may be less stressful than keeping them in crates allowing vertical movements of the birds.     

环境温度和日粮能量水平对鸡血浆皮质酮水平的影响

本试验使用６×２因子设计，研究了环境温度（５℃～３５℃，６个处理）和日粮能量浓度（２．８和３．２Ｍｃａｌ／ｋｇ，２个水平）对巴布考克型种公鸡血浆皮质酮水平的影响。结果表明：环境温度高于２５℃时，鸡血浆皮质酮水平显著升高且随温度的升高而升高，而当环境温度下降至５℃～２５℃时，血浆皮质酮水平没有显著变化；日粮能量浓度对鸡血浆皮质酮水平没有显著影响     

Corticosterone in Commercial Broilers

The welfare of commercially produced broilers is of concern to producers and consumers. When birds are reared under stressful conditions they often exhibit several adaptive responses. The major response is secretion of the stress hormone, corticosterone (CS), by the adrenal glands. The objective of this study was to assess welfare of commercially reared broilers by determining plasma CS concentrations at various times during grow out. Results show that CS concentrations of all birds tested remained in the nonstress range. The conclusion of this study is that commercial production of broilers in tunnel-ventilated houses that maintained temperatures in the comfort zone and light at low intensities did not cause stress as measured by circulating blood levels of CS.     

Social dominance‐related major urinary proteins and the regulatory mechanism in mice

Major urinary proteins (MUPs) have been proven to be non‐volatile male pheromones in mice. Here, we aimed to elucidate the relationship between MUPs and dominance hierarchy, and the underlying molecular mechanisms. Dominance–submission relationship was established by chronic dyadic encountering. We found that at the urinary protein level and hepatic mRNA level, the expression of major MUPs, including Mup20, was enhanced in dominant males compared with subordinate males, indicating that MUPs might signal the social status of male mice. Meanwhile, the mRNA level of hepatic corticotropin releasing hormone receptor 2 (CRHR2) was higher in subordinate male mice than in dominant male mice. Castration also enhanced the expression of CRHR2, but suppressed that of MUPs. CRHR2 agonist treatment reduced the expression of MUPs in liver. However, male social status failed to exert significant influence on serum testosterone and corticosterone as well as the mRNA expression of their receptors. These findings reveal that some MUPs, especially Mup20, might constitute potential dominance pheromones and could be downregulated by hepatic CRHR2, which is possibly independent of androgen or corticosterone systems.     

Vitamin C supplementation has no effect on American bullfrog's immune response

American bullfrog (Lithobates catesbeianus) is the only species raised in Brazilian commercial frog farms, and the intensive culture of these animals has gained great popularity in Brazil over the past several years. Stress is one of the major obstacles in frog culture. To minimise this problem, the aim of the present study was to investigate the role of added vitamin C in the diet of American bullfrogs as an antistress factor through the assessment of plasma corticosterone, leucocyte levels and macrophage activation in animals raised in confinement. The experimental design was entirely randomised, with six treatments (supplementation of 0, 250, 500, 750, 1000 and 2000 mg of vitamin C/kg of feed) and four replications. The plasma corticosterone level, leucocyte level and macrophage activation were evaluated. It was concluded that vitamin C had no influence on the evaluated parameters due to the possible adaptation of the animals to life in captivity (domestication). The results of this research indicate that farmers should not increase the levels of vitamin C in commercial feeds because this would only enhance production costs.     

Physical Stress Induced Reduction of Proliferating Cells and Differentiated Neuroblasts Is Ameliorated by Fermented Laminaria japonica Extract Treatment

Laminaria japonica is widely cultivated in East Asia, including South Korea. Fucoidan, a main component of L. japonica, protects neurons from neurological disorders such as ischemia and traumatic brain injury. In the present study, we examined the effects of extract from fermented L. japonica on the reduction of proliferating cells and neuroblasts in mice that were physically (with electric food shock) or psychologically (with visual, auditory and olfactory sensation) stressed with the help of a communication box. Vehicle (distilled water) or fermented L. japonica extract (50 mg/kg) were orally administered to the mice once a day for 21 days. On the 19th day of the treatment, physical and psychological stress was induced by foot shock using a communication box and thereafter for three days. Plasma corticosterone levels were significantly increased after exposure to physical stress and decreased Ki67 positive proliferating cells and doublecortin immunoreactive neuroblasts. In addition, western blot analysis demonstrated that physical stress as well as psychological stress decreased the expression levels of brain-derived neurotrophic factor (BDNF) and the number of phosphorylated cAMP response element binding protein (pCREB) positive nuclei in the dentate gyrus. Fermentation of L. japonica extract significantly increased the contents of reduced sugar and phenolic compounds. Supplementation with fermented L. japonica extract significantly ameliorated the increases of plasma corticosterone revels and decline in the proliferating cells, neuroblasts, and expression of BDNF and pCREB in the physically stressed mice. These results indicate that fermented L. japonica extract has positive effects in ameliorating the physical stress induced reduction in neurogenesis by modulating BDNF and pCREB expression in the dentate gyrus.     

不同周龄蛋鸡攻击行为与五羟色胺、皮质酮的相关性分析

为探讨蛋鸡攻击行为与五羟色胺、皮质酮的相关性,选用1日龄京白939雏鸡96只,随机分为6个重复,每重复16只,采用瞬时观察法和连续观察法筛选不同周龄攻击行为有差异的蛋鸡,结合ELISA和qRT-PCR方法测定蛋鸡血清激素水平和5-HT1A受体mRNA表达量的变化。结果显示:蛋鸡的攻击行为随周龄的增加呈现逐渐上升的趋势(P<0.05);整体看,血清五羟色胺(5-HT)含量随周龄的增加呈下降趋势,皮质酮(CORT)呈现上升趋势(P<0.05),而下丘脑5-HT1A受体mRNA表达量随周龄增加有上升的趋势(P<0.05或P<0.01)。Pearson相关分析结果显示,蛋鸡攻击行为与血清五羟色胺(5-HT)呈极显著负相关(R=-0.741,P<0.01),与皮质酮(CORT)呈显著正相关(R=0.751,P<0.01)。综上所述,血清激素水平与蛋鸡攻击行为有一定联系,5-HT1A受体基因可能参与调控蛋鸡的攻击行为。     

Physiological performance of quails that underwent dietary and pharmacological manipulation of cholesterol

The present work evaluated whether dietary and pharmacological interference on cholesterol synthesis were capable of inducing alterations in blood and yolk cholesterol levels and the secretion of corticosterone metabolites. Forty‐five 40‐day‐old quails were divided into three experimental groups: vegetal fat diet, 2% beef fat (tallow) diet and vegetal fat diet with simvastatin administration (3.13 mg/kg/day). During all experiments, the animal weights and food consumption were recorded and blood and faecal samples (days 0, 15, 30, 45 and 60), as well as eggs (days 30, 45 and 60), were collected. Analysis of serum and yolk cholesterol was performed and faecal corticosterone levels were measured. No differences were observed on blood cholesterol or faecal corticosterone between all treatments, despite a tendency of increased cholesterol in the group with the animal fat diet. However, quails submitted to an animal fat diet displayed an increase in yolk cholesterol at day 30 of the treatment and the egg yolks of quails treated with simvastatin exhibited a decrease in cholesterol content by the end of the treatment at 60 days. These results improved the knowledge regarding the physiology of quails and offered support to other studies concerning the consequences of the pharmacological treatment and the dietary manipulation of cholesterol levels.