本试验旨在通过研究淀粉饲粮鸡表观代谢能值的变异来源,探讨排空强饲法测定鸡饲料表观代谢能值的精度。试验采用单因素完全随机设计,将48只成年黄羽肉鸡公鸡随机分成2组(每组6个重复,每个重复4只鸡),分别测定强饲量为40和25 g淀粉饲粮的表观代谢能值,共重复测定4个批次。结果表明: 1)强饲量为40 g时,4个批次在表观代谢能值上均无显著差异(P>0.05),4个批次表观代谢能值的批内、批间和总变异系数分别为5.39%、1.89%和5.27%;强饲量为25 g时,4个批次在表观代谢能值上具有显著差异(P<0.05),其中第6批次显著地低于第5批次和第7批次的相应值(P<0.05),4个批次表观代谢能值的批内、批间和总变异系数分别为1.97%、1.53%和2.36%。强饲量为25 g时,鸡体重损失、强饲鸡干物质排泄量和强饲鸡总能排泄量的批内、批间和总变异系数均比强饲量40 g时的相应值低。2)在淀粉饲粮表观代谢能值的方差(变异)来源中,当强饲量为40 g时,强饲鸡的干物质排泄量的变异、排泄物总能含量的变异和强饲量的变异对总变异的贡献分别为96.46%、3.23%和0.30%;当强饲量为25 g时,三者的贡献分别为67.72%、24.51%和7.76%。由此可见,强饲量为40 g时,淀粉饲粮表观代谢能值的变异较大,而强饲量为25 g时,其表观代谢能值的变异较小。在表观代谢能值测定的变异来源中,排泄物的质量是主要因素。

This experiment was conducted to investigate the precision of empting-force feeding method for measuring the apparent metabolizable energy of corn starch diets in broilers. A single factorial completely randomized design was adapted in this experiment. Forty-eight 18-week-old yellowed-feathered broilers were divided into 2 groups with 6 replicates per group and 4 birds per replicate. The apparent metabolizable energy of corn starch diets was repeatedly determined at a force-feeding amount of 40 or 25 g using empting-force feeding method in 4 batches, respectively. The results showed as follows: 1) in the treatment of 40 g per bird for the force-feeding amount, there was no significant difference in the apparent metabolizable energy determined among 4 batches (P>0.05), and the variation coefficients of within-batch, between batch and total of apparent metabolizable energy were 5.39%, 1.89% and 5.27%, respectively; in the treatment of 25 g per bird for the force-feeding amount, there was significant difference in the apparent metabolizable energy determined among 4 batches (P<0.05), the apparent metabolizable energy of corn starch diets determined in the sixth batch was significant lower than that of the apparent metabolizable energy determined in the fifth and seventh batches (P<0.05), and the variation coefficients of within-batch, between batch and total of the apparent metabolizable energy were 1.97%, 1.53% and 2.36%, respectively. Compared with the treatment of 40 g per bird for the force-feeding amount, the variation coefficients of within-batch, between batch and total of the body weight losses, dry excreta from force-fed birds and gross energy output from force-fed birds of 25 g per bird for the force-feeding amount were lower. 2) In the treatment of 40 g per bird for the force-feeding amount, the contribution of the variance of dry excreta from force-fed birds, gross energy content of excreta from force-fed birds and force-feeding amount to the variance of apparent metabolizable energy of corn starch diets were 96.46%, 3.23% and 0.30%, respectively. In the treatment of 25 g per bird for the force-feeding amount, the contribution of the variance of dry excreta from force-fed birds, gross energy content of excreta from force-fed birds and force-feeding amount to the variance of apparent metabolizable energy of corn starch diets were 67.72%, 24.51% and 7.76%, respectively. In conclusion, the variation of apparent metabolizable energy of corn starch diets determined in the treatment of 40 g per bird for the force-feeding amount is greater than that in the treatment of 25 g per bird for the force-feeding amount. The variation of dry excreta from force-fed birds is the main source contributed to the variance of the apparent metabolizable energy of corn starch diets.