中文摘要：

目的：研究热应激对肉鸡肝肾功能的影响及甜菜碱的缓解作用。方法：选择60只14 d的AA肉鸡,随机均分为对照组、热应激组和甜菜碱组,对照组按肉鸡标准饲养环境温度饲养;其余二组为热应激组,饲养温度设定为32±1℃。其中热应激组饮用自来水,甜菜碱组饮用0.2%的甜菜碱水溶液。分别饲喂至8、35 d,翅下静脉采血2 m L,分离血清,测定血清肝肾功能指标。结果：28 d时,热应激组与对照组相比,血清天门冬氨酸氨基转移酶、单胺氧化酶活性和尿酸、尿素氮、肌酐含量显著升高（P〈0.05或P〈0.01）;甜菜碱组与热应激组相比,天门冬氨酸氨基转移酶活性、尿素氮、尿酸含量显著下降（P〈0.05或P〈0.01）。35 d时,热应激组与对照组对比,血清单胺氧化酶活性和尿酸、尿素氮、肌酐含量显著升高（P〈0.01）。甜菜碱组与热应激组对比,单胺氧化酶活性和血清尿素氮、肌酐含量显著降低（P〈0.05或P〈0.01）。结论：热应激可明显导致肝肾功能损伤,甜菜碱可以有效地缓解热应激对肉鸡肝肾功能的损伤。

英文摘要：

Objective： To investigate the effects of heat stress on hepatic and renal function in broilers and the alleviation of betaine. Methods： 60 14-day AA broilers were randomly divided into control group,heat stress group and betaine group. Control group was fed according to the standard procedure. The other two groups were fed at the temperature of 32 ± 1 ℃. Heat stress group drank tap water and betaine group drank tap water containing 0. 2% betaine. 2 m L blood samples were collected from the wing vein on day 28 and 35 of age. Serum indicators about liver and renal function were measured. Results： The activities of serum aspartate aminotransferase,monoamine oxidase and the content of uric acid,urea nitrogen and creatinine were significantly increased（ P〈0. 05 or P〈0. 01） in the heat stress group compared with the control group on day 28. Aspartate aminotransferase,uric acid and urea nitrogen decreased significantly（ P〈0. 05 or P〈0. 01） in betaine group when compared with heat stress group at the same time. On day 35,serum monoamine oxidase activity and uric acid,urea nitrogen and creatinine content increased significantly in heat stress group（ P〈0. 01） when compared with control group. The activity of monoamine oxidase and the levels of serum urea nitrogen and creatinine in betaine group were significantly lower than those in heat stress group（ P〈0. 05 or P〈0. 01）. Conclusion： Heat stress has negative effects on liver and kidney function in heat stressed broilers,and betaine can effectively alleviate the negative effects in part.