循环高温对蛋鸡生产性能、蛋壳品质及钙磷代谢的影响

本试验旨在模拟夏季蛋鸡舍内的循环高温,研究不同温度对蛋鸡生产性能、蛋壳品质及钙磷代谢的影响。选取28周龄高产海兰褐蛋鸡288只,随机分为21℃适温组(自由采食)、27~30℃循环高温组(自由采食)、29~35℃循环高温组(自由采食)和21℃采食配对组(按前1 d 29~35℃循环高温组的采食量饲喂),每个组6个重复,每个重复12只鸡,分别饲养于4个人工环境控制舱内,试验期4周。结果表明:与21℃适温组相比,27~30℃循环高温组蛋鸡平均日采食量、体增重和平均蛋重显著降低(P0.05),蛋壳强度显著降低(P0.05),蛋鸡钙、磷的代谢率差异不显著(P0.05),但钙、磷的吸收量显著降低(P0.05),除蛋黄颜色显著降低(P0.05)外,鸡蛋品质其他相关指标差异不显著(P0.05);而29~35℃循环高温组除平均日采食量、体增重和平均蛋重显著降低(P0.05)外,产蛋率同样显著降低(P0.05),蛋壳厚度和蛋壳强度均显著降低(P0.05),破蛋率显著升高(P0.05),蛋鸡钙、磷的代谢率差异不显著(P0.05),而钙、磷吸收量同样显著降低(P0.05),鸡蛋蛋白高度和蛋黄颜色均显著降低(P0.05)。与21℃采食配对组相比,29~35℃循环高温组平均蛋重显著降低(P0.05),料蛋比显著提高(P0.05),蛋壳强度显著降低(P0.05),钙、磷的代谢率和吸收量差异不显著(P0.05),鸡蛋品质差异不显著(P0.05)。结果提示,夏季鸡舍内温度在27~30℃波动即可显著降低蛋鸡的体增重、平均蛋重和蛋壳品质;而29~35℃不仅显著降低蛋鸡的体增重、产蛋率、平均蛋重以及蛋壳品质,还显著影响鸡蛋的蛋白高度和蛋黄颜色。高温对蛋鸡产蛋性能及蛋白高度和蛋黄颜色的影响可能与降低采食量有关;高温可能直接影响蛋壳的形成,也可能由于降低钙、磷吸收量影响蛋壳品质。

Effect of Cyclic High Temperature on Performance,Egg Shell Quality and Metabolism of Calcium and Phosphorous of Laying Hens

The aim of present experiment was to simulate the variation of high ambient temperature in laying hen house in summer, and evaluate the effects of different cyclic high temperature on performance, egg quality and metabolism of calcium and phosphorus of laying hens. A total of 288 Hy-Line Brown hens at 28 weeks of age were randomly divided into 4 groups with 6 replicates each and 12 hens in each replicate and housed in 4 artificially controlled environment chambers. Four groups were 21 ℃ normal thermal group ( ad libitum) , 27 to 30 ℃ cyclic high-temperature group ( ad libitum) , 29 to 35 ℃ cyclic high-temperature group ( ad libitum) and 21 ℃ pair-feeding group ( fed the last daily feed consumption of chickens in 29 to 35 ℃ high cyclic tem-perature group ) , respectively. The experiment lasted for 4 weeks. The results showed that compared with 21 ℃ normal thermal group, the average daily feed intake, body weight gain, average egg weight, egg shell strength and yolk color were significant decreased in 27 to 30℃ cyclic high-temperature group ( P<0.05) , and there was no significant difference in the other egg quality related indices between two groups ( P>0. 05 ) , while the average daily feed intake, body weight gain, average egg weight, laying rate, egg shell strength, egg shell thickness, albumen height and yolk color were all significant decreased ( P<0.05) in 29 to 35 ℃ cy-clic high-temperature group. Meanwhile, the metabolic rates of calcium and phosphorus of chickens in 27 to 30 ℃ cyclic high-temperature group and 29 to 35 ℃ cyclic high-temperature group had no significant differ-ence compared with 21℃ normal thermal group ( P>0.05) , but the absorption of calcium and phosphorus was significant decreased (P<0.05). Compared with 21 ℃ pair-feeding group, the average egg weight and shell strength were significantly decreased ( P<0.05) , and the ratio of feed to egg was significantly increased ( P<0.05) , while the egg quality, metabolic rates and absorption of calcium and phosphorus were not significantly different (P>0.05) in 29 to 35 ℃ cyclic high-temperature group. The results of present study demonstrated that body weight gain, average egg weight and egg shell quality were significantly decreased under 27 to 30 ℃and 29 to 35℃ cyclic high temperature, while the laying rate, albumen height and yolk color were also signifi-cant decreased under 29 to 35 ℃. The effects of high ambient temperature on laying performance, albumen height and yolk color of laying hens may be associated with the decrease of feed intake. The high temperature may have direct effects on egg shell formation, or the decreasing in absorption of calcium and phosphorus un-der high temperature may also affect the egg shell quality.