甜菜碱替代蛋氨酸对肉鸡生长、养分代谢及血清生化指标的影响

Effects of DL-methionine replacement with betaine on growth performance,apparent nutrients utilization and serum profile of broilers

选取192只1日龄AA肉仔鸡随机分成4组,每组6个重复,每个重复8只鸡.对照组饲喂玉米—豆粕型基础日粮(前后期分别添加0.14%和0.08%DL-蛋氨酸),试验组分别以等量的甜菜碱替代基础日粮中DL-蛋氨酸添加量的25%、50%和100%,研究甜菜碱替代蛋氨酸对肉鸡生产性能、养分表观利用率、器官指数和血清生化指标的影响.结果表明:与对照组相比,甜菜碱替代蛋氨酸对肉鸡生产性能和器官指数无显著影响(P>0.05),但25%替代组42 d的肝脏指数显著低于50%替代组(P<0.05);25%、50%和100%替代组均可提高粗蛋白的表观利用率,分别提高6.90%(P>0.05)、11.47%(P<0.05)和3.04%(P>0.05),而对干物质、有机物和粗脂肪的表观利用率无显著影响(P>0.05);50%和100%替代组显著降低21 d的血清总蛋白含量和尿素氮浓度,提高42 d的甘油三酯浓度,100%替代组还显著降低21 d的球蛋白含量(P<0.05).结果提示,甜菜碱替代玉米—豆粕型日粮中的DL-蛋氨酸可提高粗蛋白的表观利用率,对肉鸡的生产性能无影响,以替代DL-蛋氨酸添加量的25%较合理.

This study was aimed to investigate the effects of DL-methionine （DL-Met） replacement with betaine on growth perform- ance, apparent nutrients utilization, organ indexes and serum profile in broilers. A total of 192 1-day-old Arbor Acres chicks were randondy divided into 4 groups with 6 replicates of 8 birds, receiving a control basal diet containing 0.14% and 0.08% DL-Met dur- ing 1-21 and 22-42 d, respectively, and the test diets in which the DL-Met in the basal diet was replaced by equivalent betaine at 25%, 50% and 100%, respectively. Compared with control, broilers had similar growth performance and organ indexes in betaine inclusion groups （P〉0.05）, but liver index was lower in 25% betaine replacement than that of 50% betaine replacement （P〈 0.05）. Compared with control, broilers had higher apparent utilization of crude protein in betaine inclusion groups, which increased 6.90% （P〉0.05）, 11.47% （P〈0.05） and 3.04% （P〉0.05） respectively. No differences were observed in the apparent utilization of dry matter, organic matter and ether extract among groups. A higher betaine replacement （50% and 100%） reduced the content of 21 d serum total protein and urea nitrogen, but increased 42 d triglycerlde content （P〈0.05）. In addition, the complete replace- ment by betaine reduced 21 d globulin content （P〈0.05）. It was suggested that the replacement of DL-Met in corn-soybean meal di- et by betaine resulted in increased apparent utilization of crude protein and similar growth performance. It is more reasonable to re- place 25% DL-Met with betaine in corn-soybean meal diet.