蛋白酶对22～42日龄肉鸡屠宰性能、肠道形态结构和养分消化率的影响

Effects of protease on slaughter performance,intestinal villi structure and nutrient digestibility of 22- to 42-day-old broilers

为了研究蛋白酶对22~42日龄肉鸡屠宰性能、肠道形态结构和养分消化率的影响,选取600羽21日龄爱拔益加（AA）肉鸡,随机分为5个处理,每个处理6个重复,每个重复20羽,公母各半。单因子试验设计,对照饲喂基础日粮,试验Ⅰ组~Ⅳ组分别在对照组饲粮中添加50、100、200和400 g/t蛋白酶,试验周期21 d。结果表明：肉鸡腹脂率试验Ⅱ组显著低于试验Ⅲ组（P〈0.05）,其他屠宰性能指标差异不显著（P〉0.05）。肉鸡空肠隐窝深度对照组和试验Ⅱ组显著低于试验Ⅲ组（P〈0.05）,空肠绒隐比（V/C）试验II组显著高于试验Ⅰ组和试验Ⅳ组（P〈0.05）;肉鸡回肠绒毛长度试验Ⅰ组显著高于试验Ⅲ组和Ⅳ组（P〈0.05）,肉鸡回肠隐窝深度4个添加蛋白酶组显著低于对照组（P〈0.05）,肉鸡回肠V/C试验Ⅳ组显著高于对照组和试验Ⅰ、Ⅱ、Ⅲ组（P〈0.05）。添加蛋白酶显著提升了谷氨酸（Glu）、甘氨酸（Gly）、丙氨酸（Ala）、异亮氨酸（Ile）、组氨酸（His）、赖氨酸（Lys）、精氨酸（Arg）和总氨基酸（TAA）消化利用率（P〈0.05）。由此可见,肉鸡生长后期在饲粮中添加蛋白酶能够一定程度上维持肠道健康、促进养分的消化吸收、提高屠宰性能,蛋白酶添加量以100 g/t效果最佳。

The experiment was designed to study the effects of protease on slaughter performance,intestinal villi structure and nutrient digestibility of 22-to 42-day-old broilers.A total of 600 healthy Arbor Acres broilers at 21 days old with body weights（1138.91±4.78） g were randomly assigned to 5 groups with 6 replicates per group and 20 broilers per replicate.Broilers in the control group were fed a basal diet,and broilers in the group Ⅰ to group Ⅳ were fed the basal diet supplemented with 50,100,200 and 400 g/t protease,respectively.The experiment lasted for 21 days.The results showed that percentage of abdominal fat in the group Ⅱ was lower significantly than that in the group Ⅲ（P〈0.05）.But the other slaughter performance indexes were no significant differences between groups（P〉0.05）.The Crypt depth of jejunum in the control group and group Ⅱ were lower significantly than that in the group Ⅲ（P〈0.05）.V/C of jejunum in the group Ⅱwas higher significantly than that in the group Ⅰ and group Ⅳ（P〈0.05）.Length of ileal villus in the group Ⅰ was higher significantly than that in the group Ⅲ and group IV（P〈0.05）.The Crypt depth of ileum in the four protease groups were lower significantly than that in the control group（P〈0.05）.V/C of ileum in the group Ⅳ was higher significantly than that in the other groups（P〈0.05）.Protease supplementation in diet significantly improved the digestibility of Glu,Gly,Ala,Ile,His,Lys,Arg and TAA（P〈0.05）.In conclusions,diet supplemented protease in the stage of 22-to 42-day-old broilers can keep intestinal healthy,promote digestion and absorption efficiency of nutrients,then improve the slaughter performance.The appreciate agent of protease supplementation under this experiment condition is 100 g per ton diet.