高温应激对肉仔鸡的影响及补铬的效果研究

IMPACT OF HEAT STRESS ON BROILERS AND THE EFFECTSOF SUPPLEMENTAL YEAST CHROMIUM

采用２×２因子设计，４组４周龄肉仔母鸡分别饲喂实用日粮及在此基础上补加０．４０ｍｇ／ｋｇ酵母铬的试验日粮，并分别放入适中温度（２２℃）及受热条件下（每天９：００～１９：００维持３８℃，其余时间维持在３０℃）至６周龄。受热６ｄ后注射牛血清白蛋白（ＢＳＡ）。热应激显著降低了体增重、采食量、饲料转化效率、肾上腺、胸腺、法氏囊和脾脏的相对重量、异嗜性白细胞对淋巴细胞的比率、血清甘油三脂、Ｔ４、Ｔ３和胰岛素含量，提高了血清葡萄糖、胆固醇、ＢＳＡ抗体效价。在热应激条件下，补加０．４０ｍｇ／ｋｇ酵母铬能减轻以上因热应激而发生的变化，而在适中温度下，酵母铬却无太大作用。

オccording to 2×2 factorial design,four groups of 4weekold female broiler chicks were fed adlib.on a practical ration supplemented with or without 0.40mg/kg chromium(yeast chromium)under either thermoneutral(22℃)or heated(36℃ from 9:00 to 19:00 and 30℃ for the rest time of each day)conditions to 6 weeks of age.Chicks were challenged with BSA 6 days postheating.High temperature significantly reduced body weight gain,feed intake,feed efficiency,relative weights of thymus,bursa and spleen,heterophil/lymphocyte ratio,concentrations of triglyceride,T4,T3 and insulin,while increasing serum glucose,cholesterol and antiBSA antibody levels.Under heated contitions,0.40mg/kg chromium supplementation alleviated many of detrimental effects of heat stress.No significant influence with chromium supplementation was observed under thermoneutral conditions.