酵母铬对不同应激状态蛋鸡产蛋性能及血清生化指标的影响

选20周龄感染鸡传染性鼻炎、25周龄康复的罗曼产蛋鸡450只 ,随机等分5组 ,在相同基础日粮中添加0(对照)、0.2、0.4、0.6及0.8mg/kg铬量的酵母铬 ,经2周高温期预试、5周高温期及3周舒适期正试。结果表明 :(1)与舒适期相比 ,酵母铬显著提高热应激期产蛋率(P<0.01);补铬有降低试验期蛋重的趋势(P>0.05)。(2)热应激期高浓度酵母铬显著提高血清T4、胰岛素和肌酸激酶水平(P<0.01或P<0.05) ;降低了血糖水平(P<0.05)。低浓度酵母铬可提高试验期蛋鸡血清碱性磷酸酶含量(P<0.05) ,血清蛋白和胆固醇则受鸡的应激和生理状态及铬水平的影响

EFFECTS OF CHROMIUM YEAST ON LAYING PERFORMANCE AND SERUM BIOCHEMICAL PARAMETERS FOR LAYERS UNDER DIFFERENT STRESS

Lohmann brown layers infected with Avian Rhinotracheitis at 20 week of age and recovering at 25 week of age were randomly divided into five groups,one was fed with the basal diet,as the control;other four groups were fed with the basal diet added with 0.2, 0.4,0.6 or 0.8mg/kg chromium yeast(CrY) respectively.After 2 weeks under high temperature as pretrial.The trail experienced 5 week under high temperature and following 3 week thermoneutrality period as formal trail.The experimental results were as follows:(1)The laying rates of hens were significantly (P<0.01)improved with the different concentrations of CrY supplemented in diets during heat stress phase,but egg weights of all treatments showed a decreasing trend (P>0.05)compared with that of the control in whole trail period.(2)The contents of thyroxine(T4),insulin and creatine phosphokinase in serum were significantly increased in heat stress phase(P<0.01 or P<0.05) due to the supplementation of high level of CrY in diet,meanwhile,the contents of glucose were reduced(P<0.05).The content of alkaline phosphatase in serum at low level of CrY were increased by the end of the trail(P<0.05).The contents of protein and cholesterol in serum were influenced by the heat stress and physiological conditions of the layers or by the level of CrY in diet.