Waldroup P W, Anthony N B, Waldroup A L
Poultry Science Department, University of Arkansas, Fayetteville 72701, USA.
Poult Sci. 1998 May;77(5):702-13. doi: 10.1093/ps/77.5.702.
Male turkeys of two commercial Large White strains (Nicholas 88, BUT 6) were subjected to growth restriction by means of reducing amino acid (AA) content of diets to a minimum of 75% of NRC (1994) suggested levels. There were three periods when diets containing 75% of NRC recommended AA for that age period were fed ad libitum: 0 to 3 wk, 0 to 6 wk, or 6 to 12 wk. A fourth (control) group was not restricted in AA content at any time. When turkeys were not fed the AA-restricted diets they were fed diets formulated to meet a minimum of 100, 110, or 120% of NRC (1994) AA recommendations, which resulted in a 3 x 4 factorial arrangement of treatments with three AA levels by four restriction times. Four pens of 12 males each were fed each AA by restriction time combination. At 18 wk, all birds were scored individually for leg condition and representative samples of turkeys were processed for parts yield. Birds fed restricted diets from 0 to 6 or 6 to 12 wk had significantly lower BW at 18 wk than control birds. Birds fed the restricted diets from 0 to 3 wk did not differ significantly in 18-wk BW compared to control birds but the magnitude of difference was similar to that observed at the end of the restriction period. Feed utilization was not improved by early AA restriction. Restricting early growth resulted in a significantly higher incidence of birds with no leg disorders and a lower incidence of birds with moderate leg disorders than control birds. Feeding higher AA levels during realimentation resulted in a greater severity of leg disorders. Breast meat yield was depressed significantly as severity of early restriction increased. Increasing dietary AA above NRC (1994) recommended levels generally improved performance during realimentation but was not able to compensate for reduced gains during restriction.
选取两个商用大白火鸡品系（尼古拉斯88、巴特6）的雄性火鸡，通过将日粮中氨基酸（AA）含量降至美国国家研究委员会（1994）建议水平的至少75%来实施生长限制。有三个时期自由采食含该年龄段75%美国国家研究委员会推荐氨基酸量的日粮：0至3周龄、0至6周龄或6至12周龄。第四组（对照组）在任何时候都不限制氨基酸含量。当火鸡不饲喂氨基酸限制日粮时，给它们饲喂按美国国家研究委员会（1994）氨基酸推荐量的至少100%、110%或120%配制的日粮，从而形成了一个3×4的析因处理安排，即三个氨基酸水平和四个限制时间。每种氨基酸与限制时间组合下，用四个栏舍，每个栏舍饲养12只雄性火鸡。18周龄时，对所有火鸡个体的腿部状况进行评分，并对火鸡代表性样本进行胴体产率分析。0至6周龄或6至12周龄饲喂限制日粮的火鸡，18周龄时体重显著低于对照火鸡。0至3周龄饲喂限制日粮的火鸡，18周龄时体重与对照火鸡相比无显著差异，但差异幅度与限制期结束时观察到的相似。早期氨基酸限制并未提高饲料利用率。限制早期生长导致腿部无疾病的火鸡发生率显著高于对照火鸡，腿部中度疾病的火鸡发生率低于对照火鸡。恢复期饲喂较高氨基酸水平会导致腿部疾病更严重。随着早期限制严重程度的增加，胸肉产率显著降低。日粮氨基酸水平高于美国国家研究委员会（1994）推荐水平通常会在恢复期改善生产性能，但无法弥补限制期内体重增加减少的情况。
