Monogastric Research Centre, School of Agriculture and Environment, Massey University, Palmerston North 4442, New Zealand.
Monogastric Research Centre, School of Agriculture and Environment, Massey University, Palmerston North 4442, New Zealand.
Poult Sci. 2020 Dec;99(12):6925-6934. doi: 10.1016/j.psj.2020.09.040. Epub 2020 Sep 28.
The aim of present study was to determine the influence of the feed form (FF) on standardized ileal digestibility (SID) of nitrogen (N) and amino acids (AA) in 3 protein sources (PS) for broiler chickens. Six diets were tested in a 3 × 2 factorial arrangement of treatments involving 3 PS (meat and bone meal [MBM], soybean meal [SBM], and canola meal [CM]) in mash and pelleted forms. The basal endogenous N and AA losses were determined by offering a N-free diet in the mash form. From day 1 to 18, the birds were offered a broiler starter diet. The diets and the N-free diet were randomly assigned to 6 replicate cages (8 birds per cage) and fed from day 19 to 23. The ileal digesta were collected on day 23. The SID of N was higher (P < 0.05) in SBM followed by MBM and CM. The average SID of AA in SBM and MBM were similar (P > 0.05), and greater (P < 0.05) than that in CM. The FF had no influence (P > 0.05) on the SID of indispensable AA, the only exception being His, which was reduced (P < 0.05) by pelleting. Pelleting, however, resulted in reduction (P < 0.001) in the SID of all dispensable AA and average of AA. The AA most affected by pelleting was Cys, with a 15.4% decrease in the SID. The standardized ileal digestible contents of protein and the average of indispensable AA and dispensable AA were higher in MBM than in SBM, with CM being the lowest. Pelleting decreased (P < 0.05) the digestible protein and total digestible AA contents. These findings reveal that the FF has a substantial impact on AA digestibility estimates of feed ingredients and it must be considered in AA digestibility assays of ingredients with high protein and AA contents.
本研究旨在确定饲料形态（FF）对肉鸡 3 种蛋白质源（肉骨粉[MBM]、豆粕[SBM]和菜粕[CM]）中氮（N）和氨基酸（AA）的标准回肠可消化性（SID）的影响。采用 3×2 因子处理设计，在膨化和制粒两种饲料形态下，用 6 种日粮进行试验。通过在膨化形态下提供无氮日粮，确定基础内源氮和 AA 损失。从第 1 天到第 18 天，鸡只接受肉鸡开食料。从第 19 天到第 23 天，日粮和无氮日粮随机分配到 6 个重复笼（每个笼 8 只鸡）中进行饲喂。第 23 天收集回肠食糜。N 的 SID 在 SBM 后更高（P<0.05），其次是 MBM 和 CM。SBM 和 MBM 中 AA 的平均 SID 相似（P>0.05），高于 CM（P<0.05）。FF 对必需 AA 的 SID 没有影响（P>0.05），唯一的例外是 His，其 SID 因制粒而降低（P<0.05）。然而，制粒会降低所有非必需 AA 和 AA 平均值的 SID（P<0.001）。受制粒影响最大的 AA 是 Cys，其 SID 降低了 15.4%。与 SBM 相比，MBM 中的蛋白质、必需 AA 和非必需 AA 的平均 SID 更高，而 CM 最低。制粒降低了（P<0.05）可消化蛋白和总可消化 AA 的含量。这些发现表明，FF 对饲料成分 AA 消化率估计有重大影响，在高蛋白和高 AA 含量成分的 AA 消化率测定中必须加以考虑。
