What dietary supplementation can acclimate broiler chickens to heat stress?

本研究旨在寻找一种改善慢性热应激肉鸡生长性能的方法。1)对照组线粒体活性氧的产生在整个实验期间变化不大，而热应激组（34°C）在热暴露3、5和9 d后线粒体活性氧的产生增加，并在14 d时恢复到原始水平。2)培养从0-1日龄雏鸡的胸肌表面肌分离的成肌细胞，并将其暴露于41°C 6小时，导致细胞的ROS产生增加和蛋白质含量降低。抗氧化剂Tempol预处理1h可减弱上述变化。3)在基础日粮中添加谷氨酰胺和谷氨酸，可明显缓解热应激肉鸡增重、采食量和十二指肠绒毛高度与隐窝深度比值的下降。需要进一步的生化研究，包括肠道功能的修改，以建立一种方法来缓解压力。

The objective of this study was to find a possible method to improve growth performance of broiler chickens exposed to chronic heat stress. 1)Mitochondrial ROS production for control group showed little changes during the experimental periods, whereas that for the heat-stressed group (34°C)was increased after 3, 5 and 9 d of heat exposure and returned to original levels at 14d. 2)Myoblasts isolated from the pectoralissuperficialis muscles of 0-1 day old chicks were cultured and exposed to 41°C for 6 h, resulting in increased ROS production and reduced protein content of the cells. These changes were attenuated by pretreatment ofan antioxidant, Tempol for 1 h. 3)Supplementation of glutamine and glutamate to basal diets slightly but definitely alleviated decreases in body weight gain, food intake and, and ratio of the duodenal villus height to crypt depth of heat-stressed broiler chickens. Further biochemical studies including modifications of intestinal function are required to establish a method for alleviation of the stress.