略阳乌鸡7～12周龄可消化蛋氨酸需要量的研究

Digestible Methionine Requirement of Lueyang Black-Boned Chickens Aged from 7 to 12 Weeks

本试验旨在研究不同蛋氨酸水平对7~12周龄略阳乌鸡生长性能、组织器官发育,以及血清尿酸和尿素氮含量的影响,并结合代谢试验确定7~12周龄略阳乌鸡可消化蛋氨酸的适宜需要量。试验分为2部分,试验1选取6周龄末的略阳乌鸡600只,随机分为5组,每组6个重复,每个重复20只鸡,采用单因素试验设计,5个蛋氨酸水平分别为0.22%、0.32%、0.42%、0.52%、0.62%。试验2选取体重相近的健康成年雄性略阳乌鸡16只,随机分为2组,一组为内源校正组,体重为（2.14＆#177;0.12） kg,另一组为试验组,体重为（2.09＆#177;0.14） kg。结果表明：1）不同蛋氨酸水平对平均日采食量有极显著影响（P〈0.01）。随蛋氨酸水平的增加,平均日增重呈先升高后降低的二次曲线变化（P〈0.01,R2=0.691）。不同蛋氨酸水平对料重比的影响不显著（P〉0.05）,但随着蛋氨酸水平的增加,料重比呈先降低后升高的二次曲线变化趋势（P〉0.05,R2=0.204）。不同蛋氨酸水平对略阳乌鸡相对生长率有显著影响（P〈0.05）。2）不同蛋氨酸水平对血清尿酸和尿素氮的含量、胸肌率、腿肌率、腹脂率以及各内脏器官占体重的百分比均没有产生显著影响（P ＆gt;0.05）。3）试验2测得略阳乌鸡对蛋氨酸的表观消化率为92.05%,真消化率为94.97%。以平均日增重为评价指标,依据二次曲线模型,7~12周龄略阳乌鸡的表观可消化蛋氨酸需要量为0.326%,真可消化蛋氨酸需要量为0.336%。

This experiment was conducted to evaluate the effects of dietary methionine level on growth per-formance, the development of tissues and organs and serum urea acid and urea nitrogen contents, and com-bined a metabolic trial to determine the digestible methionine requirement of Lueyang black-boned chickens aged from 7 to 12 weeks. The experiment was divided into two parts, part 1：six hundred 6-week-old Lueyang black-boned chickens were randomly allocated into 5 groups with 6 replicates per group and 20 birds per repli-cate. A single factorial experiment containing 5 methionine levels （0. 22%, 0. 32%, 0. 42%, 0. 52% and 0. 62%） was undergone. Part 2： sixteen adult Lueyang black-boned male chickens with similar body weight were allocated into 2 groups, one group was the endogenous alignment group [ body weight, （ 2 . 14 ＆#177; 0. 12） kg], and the other group was the experimental group [body weight, （2. 09 ＆#177;0. 14） kg]. The results showed as follows：1 ） the average daily feed intake （ ADFI ） was significantly decreased by the methionine level （P〈0. 01）. The average daily gain （ADG） was increased first and then decreased quadratically with the methionine level increasing （P〈0. 01, R2 =0. 691）. Different methionine levels had no significant effect on feed/gain （F/G） （P〉0. 05）. However, with the methionine level increasing, F/G was decreased first and then increased in a quadratic trend （P〉0. 05, R2 =0. 204）. Different methionine levels significantly affected the relative growth rate [RGR（%） =100 ＆#215; body weight/initial body weight] （P〈0. 05）. 2） Different levels of methionine did not have significant impacts on the serum urea acid and urea nitrogen contents, breast muscle rate, leg muscle rate, abdominal fat percentage as well as some organ development （P〉0. 05）. 3） The ap-parent digestibility of methionine measured in the second part of the experiment was 92 . 05%, true digestibility of methionine was 94. 97%. To ADG as the evaluation index, based on the quadratic curve model, the appar-ent digestible methionine requirement of Lueyang black-boned chickens is 0 . 326%, and true digestible methio-nine requirement is 0. 336%.