1~25日龄竹丝鸡饲粮粗蛋白质需要量研究

【目的】 本试验通过研究饲粮粗蛋白质水平对1~25日龄竹丝鸡生长性能、胴体性状和血清生化指标的影响, 探讨此阶段竹丝鸡粗蛋白质营养需要量。【方法】 选取1 625只1日龄竹丝肉公雏, 根据体重一致原则随机分入5个处理组, 每组5个重复, 每个重复65只, 5个处理组粗蛋白质水平依次为18.5%、19.5%、20.5%、21.5%和22.5%, 试验期25 d。于试验结束当天, 每个重复选取接近平均体重的2只鸡屠宰, 采集血液制备血清以及分割屠体, 测定胴体性状和血清生化指标。【结果】 ①饲粮粗蛋白质水平显著影响肉鸡料重比(F/G)(P<0.05), 且料重比随粗蛋白质水平的增加呈线性和二次曲线降低(P<0.05);粗蛋白质水平对肉鸡终末体重、平均日增重(ADG)、平均日采食量(ADFI)和成活率均无显著影响(P>0.05)。②粗蛋白质水平对肉鸡屠宰率、半净膛率、全净膛率、胸肌率、腿肌率和腹脂率均无显著影响(P>0.05)。③粗蛋白质水平显著影响肉鸡血清尿素氮(BUN)和胰岛素样生长因子1(IGF-1)含量(P<0.05), 且随着粗蛋白质水平的升高, BUN和IGF-1含量均呈线性和二次曲线升高(P<0.05)。【结论】 综合上述结果, 饲粮21.5%~22.5%粗蛋白质水平可改善肉鸡生长性能, 18.5%~21.5%粗蛋白质水平可调节氮代谢; 以料重比、血清BUN和IGF-1含量为评价标准, 根据二次曲线模型估测获得1~25日龄竹丝公鸡饲粮粗蛋白质最佳水平分别为23.18%、19.20%和22.62%。

Study on Dietary Crude Protein Requirement of Silky Fowl During 1 to 25 Days of Age

【Obiective】 The aim of this experiment was to investigate the effects of dietary crude protein level on growth performance, carcass traits and serum biochemical indices of male Silky fowl during 1 to 25 days of age, to investigate the crude protein requirment of Silky fowl at this stage.【Method】 1 625 1-day-old male Silky fowl were randomly assigned to 5 groups with 5 replicates per group and 65 chickens per replicate, crude protein levels in five groups were 18.5%, 19.5%, 20.5%, 21.5% and 22.5% respectively, and the experiment lasted for 25 days.At the end of this experiment, two chickens with body weight close to the average were selected from each replicate for slaughter, blood was collected for serum preparation and carcasses were separated, carcass traits and serum biochemical indexes were determined.【Result】 ①Dietary crude protein level significantly affected F/G (P < 0.05), with the increasing of crude protein level, F/G was decreased linearly and quadratically (P < 0.05).Crude protein level had no significant effects on final body weight, average daily gain (ADG), average daily feed intake (ADFI) and survival rate (P > 0.05).②Crude protein level had no significant effects on carcass weight, half-eviscerated weight, eviscerated weight, breast muscle rate, leg muscle rate and abdominal fat rate (P > 0.05).③Crude protein level significantly affected the serum contents of BUN and IGF-1 (P < 0.05), and with the increasing of crude protein level, both contents of BUN and IGF-1 were increased linearly and quadratically (P < 0.05).【Conclusion】 In conclusion, dietary 21.5% to 22.5% crude protein could improve growth performance and 18.5% to 21.5% crude protein could regulate nitrogen metabolism.Using the F/G, BUN and IGF-1 contents as evaluation criteria, according to the quadratic curve model, the optimal dietary crude protein levels of Silky fowl aged from 1 to 25 days were 23.18%, 19.20% and 22.62% respectively.