低蛋白饲粮添加复合酶对白羽肉鸡生长性能和氮代谢的影响

Effects of low-protein diet supplemented with composite enzymes on growth performance and nitrogen metabolism of white feather broilers

试验旨在研究低蛋白饲粮中添加复合酶对白羽肉鸡生长性能、血清生化指标、消化酶活性、养分表观代谢率和氮代谢的影响。试验选取288只1日龄白羽肉鸡随机分为6组,每组6个重复,每个重复8只。试验期42 d。试验配方设计1~21、22~42 d两阶段,对照组(T1组)饲喂基础饲粮(粗蛋白含量21.28%、20.09%),T2组为低蛋白饲粮组(粗蛋白含量20.24%、19.08%),T3和T4组在低蛋白饲粮中分别添加100、200 mg/kg复合酶A,T5和T6组在低蛋白饲粮中分别添加100、200 mg/kg复合酶B。结果显示:在22~42、1~42 d,T2组、T5组和T6组料重比低于T1组(P>0.05);42 d时,T4组十二指肠胰蛋白酶活性显著高于其他组(P<0.05),T6组干物质表观代谢率显著高于T1组、T3组和T4组(P<0.05),粗蛋白表观代谢率显著高于T1组和T4组(P<0.05),氮排放率显著低于T1组和T4组(P<0.05)。研究表明,复合酶可改善低蛋白饲粮对白羽肉鸡生长后期生长性能和消化酶活性的影响,提高了粗蛋白表观代谢率,减少氮排放,且T6组添加效果较好。

The experiment aimed to investigate the effects of adding composite enzymes to low-protein diets on the growth performance,serum biochemical indicators,digestive enzyme activities,nutrient apparent metabolic rate,and nitrogen metabolism of white feathered broilers.A total of 288 one-day-old white feathered broilers were randomly divided into six groups,with six replicates per group and eight broilers per replicate.The experimental period was 42 days.The experimental diet was designed in two stages:1~21 days and 22~42 days.The control group(T1 group)was fed a basal diet with crude protein content of 21.28%and 20.09%,respectively.The T2 group was the low-protein diet with crude protein content of 20.24%and 19.08%.The T3 and T4 groups were fed low-protein diets supplemented with 100 and 200 mg/kg of composite enzyme A,respectively,and the T5 and T6 groups were fed low-protein diets supplemented with 100 and 200 mg/kg of composite enzyme B,respectively.The results showed that during the periods of 22~42 and 1~42 days,the feed conversion ratio of T2,T5,and T6 groups was lower than that of the T1 group(P>0.05).At 42 days,the trypsin activity in the duodenum of the T4 group was significantly higher than that of other groups(P<0.05),the nutrient apparent metabolic rate of dry matter in the T6 group was significantly higher than that of the T1,T3,and T4 groups(P<0.05),the apparent metabolic ratio of crude protein was significantly higher than that of the T1 and T4 groups(P<0.05),and the nitrogen excretion rate was significantly lower than that of the T1 and T4 groups(P<0.05).The study indicates that the addition of composite enzymes to the diet can improve the impact of low-protein diets on the growth performance and digestive enzyme activities of white feathered broilers during the later stages of growth,increase the nutrient apparent metabolic rate of crude protein,reduce nitrogen excretion,and the addition effect of the T6 group is relatively better.