0～21和22～42日龄黄羽肉鸡可消化蛋氨酸需要量的研究

试验一和试验二分别选用1日龄和22日龄岭南黄鸡各2 000只和1 600只,按性别和体重分成10处理组(公、母鸡各5组),每组4重复栏,每栏50(试验一)和40只鸡(试验二)。2个试验均采用5(饲粮蛋氨酸水平)×2(性别)两因子试验设计,试验一和二分别设0.35%、0.40%、0.45%、0.50%和0.55%以及0.30%、0.35%、0.40%、0.45%和0.50%5个饲粮蛋氨酸水平。结果表明:随着饲粮蛋氨酸水平提高,0～21日龄和22～42日龄公、母鸡每日总蛋氨酸摄入量和真可消化蛋氨酸摄入量呈线性或二次曲线升高(P<0.05);0～21日龄公、母鸡的日增重呈二次曲线升高(P<0.05),0～21日龄和22～42日龄公、母鸡的饲料增重比呈二次曲线降低(P<0.05或0.1)。可见,在基础饲粮中添加适量蛋氨酸改善了黄羽肉鸡的生产性能。根据二次回归模型估测黄羽肉鸡获得最佳生产性能95%处的总蛋氨酸需要量和真可消化蛋氨酸需要量,0~21日龄母鸡为0.433%~0.435%和0.404%~0.406%,公鸡为0.445%~0.454%和0.416%~0.425%,22～42日龄母鸡为0.463%和0.437%,公鸡为0.375%和0.349%。

Digestible Methionine Requirement of Yellow-Feathered Broiler Chickens from 0 to 21 and 22 to 42 Day of Age

Two experiments(Exp)were conducted to investigate the effects of DL-methionine(Met)supplementation on growth performance of the yellow-feathered broiler chicks,and evaluate Met requirements based on quadratic regression model.In Exp one and two,a total of 2 000 1-d-old and 1 600 22-d-old Linnan yellow-feathered broiler chicks were allocated by gender and body weight to ten groups(5 groups each gender),4 replication each group,50 or 40 birds each replication in Exp 1 or 2.A 5(dietary Met levels)×2(gender)factorial design was used,including the five dietary Met levels at 0.35%,0.40%,0.45%,0.50%and 0.55%in Exp one,and 0.30%,0.35%,0.40%,0.45%and 0.50%in Exp two,respectively.Results indicated that significant linear or quadratic responses to increasing dietary levels of Met were observed in daily total and true digestible Met intake of male and female birds from 0 to 21 and 22 to 42 d of age(P< 0.05),in ADG and FCR of male and female birds from d 0 to 21(P<0.05 or 0.1),and in FCR of male and female birds from d 22 to 42(P<0.05 or 0.1).In summary,supplementation of optimum Met to basal diets improved the growth performance of yellow-feathered broiler chicks.Based on optimum growth performance,the estimated total and digestible Met requirement for female birds from d 0 to 21 was 0.433%～0.435%and 0.404%～0.406%,and for male birds was 0.445%～0.454%and 0.416%～0.425%;those for female birds from d 22 to 42 was 0.463%and 0.437%,for male birds was 0.375%and 0.349%,respectively.