Digestible threonine: lysine ratio in diets for white laying hens at 42 to 58 weeks of age

SUMMARY This study was conducted to determine the ideal ratio of digestible threonine: lysine in diets for laying hens at 42 to 58 weeks of age. Two hundred forty Hy Line W-36 laying hens were used at 42 weeks of age for 16 weeks. The treatments were distributed in a completely randomized design with eight replicates and six birds each. The experimental diets were formulated with five levels of digestible threonine (0.461; 0.515; 0.569; 0.622 and 0.676%) providing the five ratio of digestible threonine: lysine (60; 67; 74; 81 and 88%) studied. The variables analyzed were: egg production; feed intake; lysine intake; threonine intake; mass egg; average egg weight; lysine use efficiencies by mass and produced eggs; feed conversion per mass and dozen eggs; Average weights yolk, albumen and shell; weight gain and final body weights of birds; and nitrogen balance. The digestible threonine: lysine ratio in the diet did not influence the analyzed variables except consumption of threonine which showed a linear effect. The ideal ratio of digestible threonine: lysine in diets for white laying hens at 42 to 58 weeks of age is 60%, which corresponds to the level of 0.461% of digestible threonine in the diet and daily intake of digestible threonine 446mg/bird.

摘要：本研究旨在确定42至58周龄产蛋鸡饲粮中可消化苏氨酸与赖氨酸的理想配比。本试验选取240只海兰W-36（Hy Line W-36）蛋鸡，于42周龄时启动试验，试验周期为16周。试验采用完全随机设计，设置8个重复组，每个重复饲养6只试验鸡。试验饲粮设置5个可消化苏氨酸水平（0.461%、0.515%、0.569%、0.622%和0.676%），以此构建5组可消化苏氨酸与赖氨酸配比梯度（60%、67%、74%、81%和88%）。本次试验测定的指标包括：产蛋率、采食量、赖氨酸摄入量、苏氨酸摄入量、总蛋重、平均蛋重、基于总蛋重与产蛋量的赖氨酸利用效率、每千克总蛋重及每打鸡蛋的饲料转化率、蛋黄、蛋清与蛋壳的平均重量、试验鸡只增重与末体重，以及氮平衡。结果表明，饲粮中可消化苏氨酸与赖氨酸的配比对除苏氨酸摄入量外的所有测定指标均无显著影响，其中苏氨酸摄入量随配比提升呈线性升高趋势。最终得出结论：42至58周龄白羽产蛋鸡饲粮的理想可消化苏氨酸与赖氨酸配比为60%，对应饲粮可消化苏氨酸水平为0.461%，每只试验鸡每日可消化苏氨酸摄入量为446mg。