日粮蛋白水平对13-18周龄略阳乌鸡生长性能、屠体性能和血清生化指标的影响

Effects of dietary crude protein on growth performance,carcass characteristics and serum biochemical indexes in Lueyang Black- boned Chickens from Thirteen to Eighteen Weeks of Age

本试验旨在研究日粮蛋白质水平对13-18周龄略阳乌鸡生长性能、屠体性能和血清生化指标的影响,以确定其适宜的蛋白质需要量。选取600只85日龄略阳乌鸡,将其随机分为5个处理,每个处理6个重复,每个重复20只鸡（公母各半）。各处理组分别饲喂代谢能相同、蛋白质含量不同的日粮。代谢能水平均为12.34 MJ/kg,蛋白水平分别为12.39%、14.20%、16.60%、18.06%和20.15%。饲养期间以重复为单位记录试验鸡的周喂料量,每3周以重复为单位记录试验鸡空腹体重（禁食12h后）。以此计算试验鸡的平均日增重、日采食量及料重比。并于18周龄末各重复分别选取接近相应处理组平均体重的鸡2只（公母各1只）,屠宰,进行屠体性能及血清生化指标的测定。结果表明：蛋白质水平对13-18周龄略阳乌鸡公鸡平均日增重未产生显著影响（P〉0.05）;其平均日采食量和料重比随日粮蛋白质水平的升高呈现显著下降的趋势（P〈0.05）。蛋白质水平对略阳乌鸡母鸡平均日增重和料重比未产生显著影响（P〉0.05）,但对平均日采食量及血清尿酸含量有显著影响（P〈0.05）。在本试验条件下,当日粮能量水平为12.34 MJ/kg时,基于日粮蛋白质水平对生长性能、屠体性能以及各血清生化指标影响的综合评估,13-18周龄略阳乌鸡公鸡和母鸡适宜的蛋白需要量均为16.60%-18.06%。

This study was undertaken to assess the effect of dietary crude protein（CP） concentrations on growth performance,carcass characteristics and serum biochemical indexes in Lueyang black-boned chicken. A total of 600 Lueyang black-boned chicks at 85 day old were randomly assigned to five treatments,each treatment contained 6 replicate pens with 10 males and 10 females. The birds fed experimental diets with the same metabolizable energy level（12. 34 MJ /kg） and different protein levels of 12. 39%,14. 20%,16. 60%,18. 06% and20. 15% from 13 to 18 weeks of age,respectively. The growth rate,feed intake and feed /gain ratio were measured at days 105 and 126. At day 126,2 chickens（1 male and 1 female） around the average weight in each treatment were selected from each pen and slaughtered to evaluate the carcass characteristics and serum selected biochemical indexes. The results showed that the CP level had no differential effect on growth rate in male chickens（P〉0. 05）,while,feed intake and feed /gain showed a significant downward trend as the CP level increases（P 0.05）. Dietary CP did not have any significant influences on growth rates and feed/gain ratio in female birds（P〉0.05）,while,the feed intake and uric acid concentration in sera（P〈0. 05） were significantly affected by CP levels. Based on comprehensive effects of dietary CP levels on growth performance,carcass characteristics and biochemical indexes in this experiment with a similar ME value（12. 34 MJ /kg）,the present results suggested that the optimal CP requirement in Lueyang black-boned chicken from 13 to 18 weeks of age was 16. 60%to 18. 06%.