低粗蛋白质饲粮中补充限制性氨基酸对大午金凤蛋鸡育雏期生长性能和氮排放量的影响

Effects of Supplementing Limiting Amino Acids in Low Crude Protein Diets on Growth Performance and Nitrogen Emission of Dawu Golden Phoenix Laying Hens during Incubation Period

本试验旨在研究低粗蛋白质饲粮中补充限制性氨基酸对大午金凤蛋鸡育雏期生长性能和氮排放量的影响。试验选取1日龄大午金凤蛋鸡384只,随机分为4组,每组6个重复,每个重复16只鸡。以对照组中限制性氨基酸含量为标准,降低另外3组饲粮粗蛋白质水平,补充限制性氨基酸(蛋氨酸、赖氨酸、苏氨酸),使其粗蛋白质水平分别达到20.02%、19.39%、18.44%、17.36%(实测值),饲粮其他营养水平均满足NY/T 33—2004的要求。1～6周龄进行6周试验,6周龄末继续观察,持续观察至20周龄。结果表明:1) 18.44%和17.36%粗蛋白质组平均日采食量、平均日增重和末体重差异不显著(P>0.05),但除18.44%粗蛋白质组平均日采食量外,均显著高于20.02%粗蛋白质组(P<0.05);随着饲粮中粗蛋白质水平的降低,补充限制性氨基酸使蛋鸡平均日采食量、平均日增重和末体重呈线性显著增长(P<0.05); 20.02%和19.36%粗蛋白质组各生长性能指标差异不显著(P>0.05)。18.44%粗蛋白质组6周龄末体重均匀度最佳。观察期间,18.44%粗蛋白质组蛋鸡体重数值均高于其他各组。2) 18.44%粗蛋白质组空肠和回肠长度显著高于20.02%粗蛋白质组(P<0.05),但与17.36%粗蛋白质组差异不显著(P>0.05)。3) 18.44%粗蛋白质组粗蛋白质表观存留率显著高于20.02%和19.39%粗蛋白质组(P<0.05),氮排放率和氮排放量显著低于20.02%粗蛋白质组(P<0.05)。综合大午金凤蛋鸡生长性能和氮排泄量可知,降低饲粮粗蛋白质水平并补充限制性氨基酸不仅有利于大午金凤育雏期蛋鸡的生长发育,还可提高氮利用率。

The purpose of this study was to investigate the effects of supplementing limiting amino acids in low crude protein diets on growth performance and nitrogen emission of Dawu Golden Phoenix laying hens during the incubation period.A total of 384 one-day-old Dawu Golden Phoenix laying hens were randomly divided into4 groups with 6 replicates in each group and 16 hens in each replicate.Based on the limiting amino acid content in control group,dietary crude protein levels in other groups were decreased,and added limiting amino acids(methionine,lysine and threonine) to achieve crude protein levels of 20.02%,19.39%,18.44% and17.36%(measured value).The other nutrition levels in the diets meet the requirements of NY/T 33—2004.The trial lasted for 6 weeks(1 to 6 weeks of age),and from the end of 6 weeks of age,an observation period lasted until 20 weeks of age.The results showed as follows:1) the average daily feed intake,average daily gain and final body weight of 18.44% and 17.36% crude protein groups had no significant difference(P >0.05),but were significantly higher than those of 20.02% crude protein group(P<0.05) except for average daily feed intake of 18.44% crude protein group.As dietary crude protein levels decreased,supplementing limiting amino acids linearly increased the average daily feed intake,average daily gain and final body weight(P<0.05),but there was no significant difference between the 20.02% and 19.36% crude protein groups(P >0.05).The 18.44% crude protein group had the best body weight uniformity.During the observation period,the body weight of 18.44% crude protein group had been at the top of the list.2) The length of the jejunum and ileum of 18.44% crude protein group was significantly higher than that of 20.02% crude protein group,but there was no significant difference of 17.36% crude protein group(P>0.05).3) The apparent retention rate of crude protein in 18.44% crude protein group was significantly higher than that of 20.02% and 19.39% crude protein groups(P< 0.05).The nitrogen emission rate and nitrogen emission of 18.44% crude protein group were significantly lower than those of 20.02% crude protein group(P<0.05).Considering the growth performance and nitrogen emission,reducing dietary crude protein levels and supplementing limiting amino acids not only facilitate the growth but also improve nitrogen utilization.