日粮添加蛋白酶对肉仔鸡生产性能、氮代谢及粪便氨气释放的影响

Effects of Dietary Protease Supplementation on Performance,Nitrogen Metabolism and Fecal Ammonia Release of Broilers

试验旨在探讨蛋白酶对肉仔鸡生产性能、氮代谢以及粪便氨气释放的影响,确定适宜的蛋白酶添加水平,为提高肉仔鸡的生产性能并减少氮的排放提供理论依据。选取体况相近且健康的1日龄AA肉仔鸡240只,随机分为4组,每组6个重复,每个重复10只。对照组饲喂基础日粮(不添加蛋白酶),试验组分别在基础日粮中添加4、8、12 U/g蛋白酶,试验期为42 d。结果表明:蛋白酶对肉仔鸡的平均日采食量无显著影响;1~21、22~42、1~42 d,8 U/g组和12 U/g组平均日增重均高于对照组(P<0.05);12 U/g组耗料增重比均低于对照组(P<0.05);蛋白酶对摄入氮无显著影响;8 U/g组在1~21 d排出氮低于对照组(P<0.05),12 U/g组在22~42 d排出氮低于对照组(P<0.05);12 U/g组各时期的氮利用率均高于对照组(P<0.05);21 d时,12U/g组血液总蛋白水平高于对照组(P<0.05),尿酸水平低于对照组(P<0.05);试验组粪便氨气释放量均低于对照组(P<0.05)。可见,蛋白酶添加水平为12 U/g有利于提高肉仔鸡的生产性能和氮利用率,并且降低粪便氨气的释放。

This study was conducted to investigate the effects of protease on performance,nitrogen metabolism and fecal ammonia release of broilers,and to determine the appropriate supplemental level of protease,so as to provide a theoretical basis for improving performance and reducing nitrogen emission of broilers.A total of 240 one-day-old AA broilers with similar body condition were randomly divided into 4 groups with 6 replicates of 10 broilers each.The dietary treatments consisted of the basal diet as control and basal diet supplemented with 4 U/g,8 U/g and 12 U/g protease,respectively.The experiment lasted for 42 days.The results showed that there was no significant difference in feed intake among all groups(P>0.05).The average daily weight gain of 8 U/g and 12 U/g was significantly higher than that of control during early period,late period and the whole period(P<0.05).The feed to meat ratio in 12 U/g was significantly lower than that of control in each period(P<0.05).There was no significant difference in nitrogen intake(P>0.05).Nitrogen excretion in 8 U/g was significantly lower than that in control group during early period(P<0.05),and in 12 U/g was significantly lower than that in control group during late period(P<0.05);N utilization efficiency in 12 U/g was significantly higher than that in control during each period(P<0.05).Total protein in 12 U/g was significantly higher than that in control(P<0.05)on d 21 and uric acid was significantly lower than that in control group(P<0.05).Ammonia gas release in 4 U/g,8 U/g and 12 U/g was significantly lower than that in control group(P<0.05).In conclusion,when protease level was 12 U/g,it was beneficial to improve the performance and nitrogen utilization rate of broilers as well as reduce the amount of ammonia released from chicken manure.