USDA-ARS Poultry Research Unit, MS, 39762, United States.
School of Environmental and Rural Sciences, University of New England, Armidale, NSW, 2351, Australia.
Poult Sci. 2022 Jul;101(7):101911. doi: 10.1016/j.psj.2022.101911. Epub 2022 Apr 8.
An experiment was conducted to evaluate the effects of varying AME concentrations and protease supplementation on broiler performance and jejunal and ileal nutrient digestibility from 1 to 35 d of age. Ross × Ross 308 male broilers (n = 1,008) were equally distributed into 48 floor pens and offered 1 of 6 dietary treatments (8 replicate pens/treatment). Dietary treatments consisted of a factorial arrangement with AME concentration (low-, moderate-, or high-AME) and supplemental protease (without or with) as the main factors. Birds and feed were weighed on 1, 15, 29, and 35 d of age to determine body BW, BW gain (BWG), feed intake (FI) and feed conversion ratio (FCR). At 15 and 29 d of age, jejunal and ileal digesta contents were collected to determine nutrient digestibility. From 1 to 15 d of age, broilers offered moderate-AME diets (P < 0.05) had 6.7, 7.1, 4.8% higher BW, BWG, FI, respectively, and a 2.1% lower FCR compared with those offered low-AME diets. Likewise, protease increased (P < 0.05) BW and BWG by 4.3 and 4.7%, respectively, and decreased (P < 0.05) FCR by 3.4%, compared with those offered the diets without protease. From 1 to 29 d of age, broilers offered high-AME diets had 2.9% lower (P < 0.05) FCR compared with those offered low-AME diets. Protease increased (P < 0.05) BW, BWG, and FI by 3.1, 3.2, and 4.2%, respectively, compared with the unsupplemented diets. From 1 to 35 d of age, broilers receiving high-AME diets had 2.9% lower (P < 0.05) FCR compared with those offered low-AME diets. Protease increased (P < 0.05) FCR by 1.0% compared with those offered unsupplemented diets. Jejunal (15 and 29 d of age) and ileal (29 d of age) starch digestibility and jejunal nitrogen digestibility (29 d of age) were lower (P < 0.05) in broilers offered high-AME diets compared with those offered low-AME diets. Both AME concentration and supplemental protease independently affected broiler performance, with responses being most apparent during early growth phases whereas digestibility measures were mainly influenced by AME concentration.
一项实验评估了不同代谢能浓度和蛋白酶添加对 1 至 35 日龄肉鸡生产性能以及空肠和回肠养分消化率的影响。罗斯 308 雄性肉鸡（n=1008）等分为 48 个栏位，接受 6 种饲粮处理（8 个重复栏位/处理）之一。饲粮处理为代谢能浓度（低、中、高）和添加蛋白酶（有或无）的析因安排，作为主要因素。在 1、15、29 和 35 日龄时，称重鸡和饲料，以确定体重 BW、体重增重（BWG）、采食量（FI）和饲料转化率（FCR）。在 15 和 29 日龄时，收集空肠和回肠食糜内容物，以确定养分消化率。1 至 15 日龄时，与低代谢能饲粮相比，饲粮中提供中代谢能（P<0.05）的肉鸡具有 6.7%、7.1%和 4.8%更高的 BW、BWG 和 FI，FCR 降低 2.1%。同样，与未添加蛋白酶的饲粮相比，蛋白酶添加分别增加（P<0.05）了 4.3%和 4.7%的 BW 和 BWG，降低（P<0.05）了 3.4%的 FCR。1 至 29 日龄时，与低代谢能饲粮相比，饲粮中提供高代谢能的肉鸡 FCR 降低了 2.9%（P<0.05）。与未添加蛋白酶的饲粮相比，蛋白酶添加分别增加（P<0.05）了 3.1%、3.2%和 4.2%的 BW、BWG 和 FI。1 至 35 日龄时，与低代谢能饲粮相比，饲粮中提供高代谢能的肉鸡 FCR 降低了 2.9%（P<0.05）。与未添加蛋白酶的饲粮相比，蛋白酶添加使 FCR 增加了 1.0%。与低代谢能饲粮相比，15 和 29 日龄时的空肠（15 和 29 日龄）和回肠（29 日龄）淀粉消化率以及 29 日龄时的空肠氮消化率降低（P<0.05）。AME 浓度和补充蛋白酶独立影响肉鸡生产性能，在早期生长阶段反应最为明显，而消化率测量主要受 AME 浓度影响。
