CIRAD, UMR 110 INTREPID, 34398 Montpellier Cedex 5, France.
J Anim Sci. 2013 Feb;91(2):613-22. doi: 10.2527/jas.2012-5572. Epub 2012 Dec 12.
Improving the sustainability of poultry production involves limiting its environmental impact and maintaining effectiveness. It has recently been shown that genetic selection on the ability of chickens to digest wheat at 23 d of age can decrease chicken excretion without decreasing BW at this age. The aim of this study was to check whether selection on digestibility modified excretion and growth performance over the whole production cycle. The 2 divergent lines selected for high (D+) and low (D-) apparent metabolizable energy corrected for 0 N balance (AMEn) values were compared with a reference line used at the beginning of the selection experiment (RL) to evaluate the potential excretion improvement that could be expected with such selection. These 3 lines were therefore compared for growth and excretion (raw and relative to feed intake, fresh and dry excreta weights, and moisture content of excreta) from 4 to 53 d. Between 4 and 7 d, 17 and 21 d, and 49 and 53 d, AMEn and N and P excretion rates were also compared between the 3 lines. Furthermore, body composition (breast meat and abdominal fat yields), bone breaking strength, and meat quality traits (lightness, redness, yellowness, and ultimate pH) were compared between lines at 53 d. Over the whole rearing period, D+ birds excreted significantly less fresh and dry excreta (-56 and -61%) than D- and RL birds (-6 and -26%). Similarly, N and P excretion rates of D+ birds were 13% to 30% less than those of D- birds and 12% to 19% less than RL birds, depending on age. These excretion differences may be related to the differential development of the gastrointestinal tract. Differences between lines were already present at 7 d for relative gizzard weight and the weight of the upper to the lower part of the gastrointestinal tract ratio. Anatomic differences were maximum at 23 d for all traits except for relative weight of the duodenum. At slaughter age, BW, breast and fat yields, and meat color did not differ between D+ and RL birds, but D- birds were fatter than D+ and RL birds. Finally, ultimate meat pH was 1% to 2% greater in RL birds than in the D+ and D- lines. In conclusion, this study showed that selection of chickens for AMEn is a possible way to reduce the environmental impact of production over the whole rearing period without a negative impact on growth, body composition, or meat quality.
提高家禽生产的可持续性涉及限制其环境影响并保持其有效性。最近已经表明，通过选择能够在 23 日龄时消化小麦的鸡的能力，可以减少鸡的排泄物排放，而不会降低该日龄时的体重。本研究的目的是检查消化率的选择是否会改变整个生产周期的排泄和生长性能。选择高（D+）和低（D-）表观代谢能校正 0 氮平衡（AME n ）值的 2 个分歧线与选择实验开始时使用的参考线（RL）进行比较，以评估这种选择可能带来的潜在排泄改善。因此，从 4 日龄到 53 日龄，比较这 3 条线的生长和排泄（排泄物的原始和相对饲料摄入量、新鲜和干燥排泄物重量以及排泄物水分含量）。在 4 日龄至 7 日龄、17 日龄至 21 日龄以及 49 日龄至 53 日龄之间，还比较了 3 条线之间的 AME n 和 N 和 P 排泄率。此外，53 日龄时还比较了线之间的体组成（胸肉和腹部脂肪产量）、骨骼断裂强度和肉质特性（亮度、红色度、黄色度和最终 pH 值）。在整个饲养期内，D+鸟类的新鲜和干燥排泄物排放量分别比 D-和 RL 鸟类少 56%和 61%（-56%和-61%）。同样，D+鸟类的 N 和 P 排泄率比 D-鸟类少 13%至 30%，比 RL 鸟类少 12%至 19%，具体取决于年龄。这些排泄差异可能与胃肠道的不同发育有关。在 7 日龄时，就相对肌胃重量和胃肠道上半部分与下半部分的重量比而言，各条线之间已经存在差异。在 23 日龄时，除了十二指肠的相对重量外，所有性状的解剖差异都达到最大。在屠宰年龄时，BW、胸肉和脂肪产量以及肉色在 D+和 RL 鸟类之间没有差异，但 D-鸟类比 D+和 RL 鸟类更胖。最后，RL 鸟类的最终肉 pH 值比 D+和 D-线高 1%至 2%。总之，本研究表明，选择鸡的 AME n 是一种可能的方法，可以在整个饲养期内减少生产对环境的影响，而不会对生长、体组成或肉质产生负面影响。
