3～6周肉仔鸡苏氨酸、色氨酸需要量的研究

Studies on the Threonine and Tryptophan Requirement of Broiler Chicken From 3 to 6 Weeks of Age

本试验研究 3～ 6周肉仔鸡苏氨酸 (Thr)和色氨酸 (Trp)的需要量。Thr和Trp各设四个水平 ,日粮总Thr的含量为 0 .66%、0 .70 %、0 .74 %和 0 .78%,真可消化Thr的含量为 0 .57%、0 .61 %、0 .65%和0 .69%;日粮总Trp的含量为 0 .1 7%、0 .1 8%、0 .1 9%和 0 .2 0 %,真可消化Trp的含量为 0 .1 5%、0 .1 6%、0 .1 7%和 0 .1 8%。采用两因子完全随机设计。对体增重、饲料转化率、氮表观存留率和血清尿酸浓度等指标进行了测定。结果表明 :3～ 6周肉仔鸡粗蛋白水平降到 1 8%仍有较好的饲养效果 ;Thr和Trp间存在交互作用 ,且对体增重和饲料转化率有显著影响 ;综合考虑各项指标 ,日粮总Thr和Trp的需要量为0 .66%和 0 .1 8%～ 0 .1 9%,真可消化Thr和Trp的需要量为 0 .57%和 0 .1 6%～ 0 .1 7%。

A 4×4 factorial completely randomized experiment was conducted to study threonine(Thr) and tryptophan(Trp) requirement of broiler chickens from 3 to 6 weeks of age. There were 16 treatment groups with three replications per treatment. Dietary total Thr levels were 0.66%,0.70%,0.74% and 0.78%,the true digestible Thr levels were 0.57%,0.61%,0.65% and 0.69%,and dietary Trp levels were 0.17%,0.18%,0.19% and 0.20%,the true digestible Trp levels wer 0.15%, 0.16%, 0.17% and 0.18%,respectively. The basal diet contained 12.97MJ/kgME,18%CP,0.66%Thr and 0.17%Trp.There was a control group with six replications at a diet of 12.97MJ/kgME,19%CP,0.77%Thr and 0.20%Trp for evaluating the effects of decreased dietary CP and AA levels.864 healthy Avian broilers of 21 days were randomly divided into 54 different groups (half male and half female). Body weight gain(BWG),feed/gain(F/G), apparent nitrogen retention ratio and serum uric acid content were measured. The results showed that decreasing broiler chick dietary CP to 18% didn't influence performance, there was a significant reciprocal effect between Thr and Trp on BWG and F/G.The requirement of the total Thr was 0.66%,and Trp was 0.18% to 0.19%, The requirement of true digestible Thr and Trp was 0.57%, 0.16% to 0.17%,respectively.