摘要
选用健康的1日龄三黄鸡1200羽(公母各半),初生重接近,随机分为4组,每组5个重复,每个重复60羽(公母各半),分别为A1、A2、A3、A4。A1组饲喂常规蛋白质水平日粮,A2组饲喂低蛋白水平日粮(0～4周蛋白质含量低3%,5～12周蛋白质含量低5%),A3组日粮在A1组日粮的基础上添加125mg/kg的PT125TM,A4组日粮在A2组日粮的基础上添加125mg/kg的PT125TM。分别在4周龄、8周龄、12周龄三个阶段测定宁都三黄鸡十二指肠内容物淀粉酶和肌胃内容物蛋白酶活性、免疫器官指数、日增重、日采食量、饲料转化率,在6周龄和12周龄测定宁都三黄鸡日粮干物质消化率和氮的表观消化率、血清中丙二醛(MDA)含量、超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)活性,在6、8、10、12周龄时测定血清中总蛋白和球蛋白含量。结果表明:PT125TM蛋白酶可提高宁都三黄鸡干物质消化率和氮的表观消化率,提高宁都三黄鸡的饲料转化率,特别是在生长发育期效果显著;提高三黄鸡抗热氧化能力,降低由于热应激造成的生产性能损失;提高蛋白质消化率,降低日粮蛋白质水平,节约蛋白质资源。
1200 one-day old Chinese yellow broiler chickens were randomly divided into four groups of 300 birds each. Each group had five replications with 60 birds per replication. The experiment lasted 12 weeks, the animals were offered different feed during 0～4weeks, 5～8weeks, 9～12weeks.The treatments included regular diet（A1）, lower protein level of diet reducing 3% during 0～4 weeks and lower protein level of diet reducing 5% during 5～12 weeks（A2）, regular diet plus 125mg/kg PT125TM（A3）, lower protein plus 125mg/kg PT125TM （A4）. Measured the activity of amylase in duodenum chyme and the activity of protease in stomach chyme, the indexes of immune organs,the chickens daily gain, daily feed intake and feed conversion ratio at 4, 8,12 weeks of age. Measured DM digestibility and protein apparent digestibility, the content of Maleic Dialdehyde （MDA）, the activity of Superoxide Dismutase （SOD） and Glutathione peroxidase （GSH-PX） in serum at 6 and 12 weeks of age.The results indicated PT125TM could improve the DM digestibility and protein apparent digestibility, improve the feed conversion ratio, especially in growing period,decrease heat stress,PT125TM could enhance the protein digestibility and decrease the protein in diet which could make the protein resource not waste.
