Ferket P R, Sell J L
Department of Animal Science, Iowa State University, Ames 50011.
Poult Sci. 1989 May;68(5):687-97. doi: 10.3382/ps.0680687.
The effect of early protein (Pr) nutrition on the carcass characteristics of turkey toms was studied. Four levels of dietary protein [100, 80, 70, or 60% of National Research Council (NRC) recommendations in 1984] were fed as isocaloric diets ad libitum from 1 to 6 wk of age. Subsequently, the four treatment groups were fed according to NRC recommendations in 1984 to 20 wk of age. Toms from all treatment groups were sampled at 6, 12, and 20 wk of age, and New York-dressed carcasses were evaluated for chemical composition and yield of commercial cuts. Fat and DM content in the carcass increased, whereas ash and crude Pr content decreased as the toms aged. Yields of breast and back increased, drumsticks and wings decreased, and thighs did not change as the toms aged. At 6 wk, percentages of carcass Pr and ash were not affected by Pr, but fat increased linearly as the level of Pr decreased (P less than .005). Breast and thigh meat yields decreased, and skin yield increased as the level of Pr decreased. Yields of bone and other carcass parts were not influenced by Pr. At 12 and 20 wk, breast and thigh meat yields and chemical composition were restored to normal proportions, irrespective of early Pr nutrition. At 20 wk of age, only breast yield was significantly reduced by 60% Pr (P less than .05). The amount of dietary Pr consumed per carcass Pr gain decreased at all stages of growth as the level of Pr decreased. Early Pr had minimal effects on relative organ weights. Toms recover from the effects of early Pr restriction on carcass parts, but restriction to the 60% level may reduce breast meat yield.
研究了早期蛋白质（Pr）营养对火鸡公禽胴体特性的影响。从1至6周龄，将四种日粮蛋白质水平[1984年美国国家研究委员会（NRC）建议量的100%、80%、70%或60%]作为等热量日粮随意投喂。随后，四个处理组按照1984年NRC的建议投喂至20周龄。在6周龄、12周龄和20周龄时对所有处理组的公禽进行采样，并对纽约加工后的胴体进行化学成分和商业切块产量评估。随着公禽年龄增长，胴体中的脂肪和干物质（DM）含量增加，而灰分和粗蛋白含量降低。随着公禽年龄增长，胸脯和背部的切块产量增加，腿和翅膀的切块产量降低，大腿的切块产量没有变化。在6周龄时，胴体蛋白和灰分的百分比不受蛋白质水平影响，但随着蛋白质水平降低，脂肪呈线性增加（P小于0.005）。随着蛋白质水平降低，胸脯和大腿肉的产量降低，而皮肤产量增加。骨骼和胴体其他部分的产量不受蛋白质水平影响。在12周龄和20周龄时，无论早期的蛋白质营养情况如何，胸脯和大腿肉的产量及化学成分都恢复到了正常比例。在20周龄时，只有60%蛋白质水平组的胸脯产量显著降低（P小于0.05）。随着蛋白质水平降低，在生长的各个阶段，每单位胴体蛋白增加量所消耗的日粮蛋白量都减少。早期蛋白质营养对相对器官重量的影响最小。火鸡公禽能从早期蛋白质限制对胴体部分的影响中恢复过来，但限制到60%的水平可能会降低胸脯肉产量。
