不同无机磷水平日粮中添加植酸酶对肉鸡生长性能及养分利用率的影响

Effects of phytase supplementation on growth performance and nutrients utilization rate in broiler chicks fed diets with different levels of inorganic phosphorus

研究了不同无机磷水平日粮中添加植酸酶对肉鸡生长性能、蛋白质及矿物质元素利用率的影响。选取1日龄肉鸡1500只，随机均分为5组，对照组以磷酸氢钙为磷源，其余为试验组，其磷酸氢钙水平分别为对照组的75％、50％、25％和0％，并添加植酸酶，各组钙磷比值在1．2—1．4之间。结果表明：无磷酸氢钙组日均采食量、日增重均显著低于对照组（P〈0．05），50％磷酸氢钙组日增重最高，料重比最低。各处理组的净蛋白利用率均高于对照组，但差异不显著（P〉0．05）。矿物质元素利用率随无机磷含量减少呈升高趋势。随无机磷水平降低，各试验组排泄物中磷含量分别比对照组依次降低了11．0％、17．9％、23．9％、28．4％。综合生长性能及养分利用率以50％磷酸氢钙添加植酸酶组（0～4周：钙0．76％，总磷0．54％；5～7周：钙0．70％，总磷0．53％）效果较好。

An experiment was conducted to study the effects of phytase supplementation in broilers fed diets with different levels of inorganic phosphorus on growth performance and nutrients utilization rate. A total of 1 500 broilers were chosen and assigned randomly to five experimental treatments. A diet adequate in inorganic phosphorus without phytase, was used as control, and the other four calcium phosphate dibasic levels which were 75% , 50% , 25% , 0% of the control were performed with phytase addition, respectively. Dietary Ca： total phosphorus （TP） ratio between 1.2 to t. 4 was controlled in all treatments. The results demonstrated that average daily feed intake （ADFI） and average daily gain （ADG） of no inorganic phosphate group was significantly lower than those of the control （P 〈0. 05 ）. ADG of 50% calcium phosphate dibasic group was the highest and feed gain ratio was the lowest in all groups. The net protein utilization （NPU） of the treatments with phytase were higher than the control group, but they were not significantly different than that of the control （ P 〉 0. 05 ）. The treatments had the increasing tendency to the utilization rate of mineral elements in response to decreasing inorganic P levels. The phosphorus contents of phytase groups were lower than those of the control group by 11.0% , 17.9% , 23.9% , 28.4% with the deceasing inorganic phosphorus levels in excretion. According to the results of growth performance and nutrients utilization rate, 50% dicalcium phosphate group （ 0 - 4 weeks ： Ca 0. 76%, TP 0. 54% ; 5 -7 weeks： Ca 0. 70% , TP 0. 53% ） appears to provide better efficacy.