日粮中添加葛根素对夏季高温高湿条件下肉牛生理生化指标的影响

Effects of Puerarin in Diet on Physiological and Biochemical Indexes of Beef Cattle under Heat Stress

为了研究葛根素对夏季高温高湿条件下肉牛生理生化指标的影响,试验选取12头健康状况良好、体重约为420kg的育肥期锦江黄牛未去势公牛,随机分为对照组和葛根素组,每组6头牛。试验牛均饲喂于夏季高温高湿条件下,葛根素组在肉牛精料中添加0.1%的葛根素提取物,试验为期60d。结果显示:1)夏季高温高湿环境下,试验期牛舍平均温湿指数高于79,肉牛处于高度热应激状态。2)葛根素组肉牛的体温在第20、40天显著低于对照组,呼吸频率在第20天比对照组显著降低(P<0.05)。3)与对照组相比,葛根素组血清三碘甲状腺原氨酸含量在试验的第30、60天分别提高了11.40%、34.26%(P<0.05),甲状腺素含量在第60天提高了17.00%(P<0.05),胰岛素含量在第30天升高了30.99%(P<0.05);皮质醇和生长激素水平与对照组无显著差异(P>0.05)。此外,葛根素组肉牛血清谷胱甘肽过氧化物酶和总抗氧化能力活性在第60天分别高于对照组38.3%和8.68%(P<0.05);免疫球蛋白G含量在第30、60天分别提高了10.83%、9.45%(P<0.05);免疫球蛋白M含量在第60天比对照组显著升高(P<0.05)。这些结果表明,饲粮中添加0.1%的葛根素可缓解夏季高温高湿条件下肉牛的热应激反应,提高热应激肉牛的免疫功能及抗氧化性能。

In order to study the effects of puerarin in diet on physiological and biochemical indexes of beef cattle under heat stress, twelve healthy and uncastrated Jinjiang yellow cattle with initial body weight of （427.27±24.06） kg were randomly divided into 2 groups with 6 cattle in each group. Animals were fed under environment of high temperature and humidity in summer. Puerarin extract （0.1%） was added in concentrate for cattle in puerarin group. The test lasted for 60 days. The results showed as follows： 1） high temperature and humidity environment in summer caused heat stress of beef cattle, the average temperature humidity index （THI） was above 79. In addition, the body temperature of puerarin group were reduced on day 20 and 40, but the respiratory rate were dropped only at 20 d compared with control group （ P 〈0.05）. 2） The levels of blood T3 with puerarin treatment were increased by 11.40% and 34.26% respectively at 30 and 60 d, T4 contents were enhanced by 17.00% at 60 d, and the contents of nsulin （INS） were increased by 30.99% at 30 d（ P 〈0.05）, but no differences were noticed about the levels of cortisol （COR） and growth hormone（GH） between two groups（ P 〈0.05）. In addition, the activity of glutathione peroxidase （GSH-Px） and total antioxidant capacity （T-AOC） of the puerarin group were increased respectively 38.3% and 8.68% on days 60, the levels of IgG were increased by 10.83% and 9.45% respectively on days 30, 60, and IgM contents were enhanced on 60 d compared with control group（ P 〈0.05）. These results indicate that dietary supplementation of 0.1% puerarin extract could alleviate heat stress response of beef cattle, and improve their antioxidant and immunity.