Prestage Department of Poultry Science, North Carolina State University, Raleigh; Departamento de Zootecnia, Universidade Federal Rural de Pernambuco, Recife, Pernambuco, Brazil.
Prestage Department of Poultry Science, North Carolina State University, Raleigh.
Poult Sci. 2021 Feb;100(2):820-834. doi: 10.1016/j.psj.2020.10.046. Epub 2020 Nov 2.
This experiment evaluated the interactive effects among xylanase (XL; 0, 8,000, 16,000, and 32,000 BXU/kg), amino acid density (AA; high and low 10% difference), and additional fat (AF; 0 or +1.17%) applied postpellet in corn-soybean meal diets with dried distillers grains with solubles on performance, energy utilization, digestibility, and carcass traits in Ross 708 male broilers. A completely randomized block (pen location) design with 16 treatments arranged factorially (4 XL levels, 2 AA, and 2 AF) was analyzed using mixed models. No significant interactions or main effects were observed for feed intake at 49 d (P > 0.05) but chicks were heavier when consuming diets containing 0 or 8,000 BXU/kg (P = 0.015), high AA (P < 0.001), and 1.17% AF (P < 0.001). Feed efficiency did not vary with XL supplementation (P > 0.05) but was improved in broilers fed the higher AA and AF diet (P = 0.015 for AA × AF). AME, GE, and CP digestibility were assessed at days 17 and 42. There were multiple interactions observed at day 17 with a significant three-way showing that AME and CP digestibility improved when increasing the XL and AF levels in the high AA fed birds compared with the low-density diets. At day 42, XL and AF significantly affected AMEn, GE, or CP digestibility; however, there was a significant interaction between XL and AF. Diets supplemented with 1.17% AF improved AMEn significantly in broilers fed the highest XL level. Breast yield was not affected by treatments, but wing yield decreased with high AA density when diets contained 16,000 BXU/kg without differences for the other diets (P = 0.04 for XL × AA). Effects of XL, AA, and AF interactions on performance and cut-up-part yields have to be considered until day 42 for most of the variables studied. However, at 49 d of age, the dietary AA density and AF did not markedly influence the response to XL in maize-based diets.
本实验评估了木聚糖酶（XL；0、8000、16000 和 32000 BXU/kg）、氨基酸密度（AA；高和低 10%差异）和额外脂肪（AF；0 或+1.17%）在添加干酒糟及其可溶物的玉米-豆粕日粮中对罗斯 708 雄性肉鸡的生产性能、能量利用、消化率和胴体特性的互作影响。采用完全随机区组（栏位位置）设计，以 16 种处理方式进行因子分析（4 种 XL 水平、2 种 AA 和 2 种 AF），使用混合模型进行分析。49 日龄时，采食量无显著互作或主效应（P＞0.05），但采食 0 或 8000 BXU/kg、高 AA（P＜0.001）和 1.17% AF（P＜0.001）日粮的鸡体重更重。XL 补充剂对饲料效率没有影响（P＞0.05），但饲喂高 AA 和 AF 日粮的肉鸡饲料效率提高（AA×AF 为 0.015）。AME、GE 和 CP 消化率分别在第 17 天和第 42 天进行评估。第 17 天观察到多种互作，其中一个三向互作具有显著意义，表明与低密度日粮相比，在高 AA 喂养的鸟类中增加 XL 和 AF 水平可提高 AME 和 CP 消化率。第 42 天，XL 和 AF 显著影响 AMEn、GE 或 CP 消化率；然而，XL 和 AF 之间存在显著互作。在饲喂最高 XL 水平的肉鸡中，添加 1.17% AF 的日粮显著提高了 AMEn。处理对胸肉产量没有影响，但当日粮中含有 16000 BXU/kg 的高 AA 密度时，翅膀产量下降，而其他日粮没有差异（XL×AA 为 0.04）。在研究的大多数变量中，直到第 42 天，还必须考虑 XL、AA 和 AF 互作对生产性能和分割部分产量的影响。然而，在 49 日龄时，日粮 AA 密度和 AF 对玉米基础日粮中 XL 的反应没有明显影响。
