Abstract

This study was conducted to determine the effects of grower diet (d11-24) digestible sulphur amino acids (SAAs) levels on performance traits, blood metabolites, and immune responses to Newcastle disease (ND) and avian influenza (AI) vaccination in the broiler chickens. Additionally, digestible SAAs requirements were determined based on nutrient dose-response data. A total of 360, 11‐day‐old male Ross-308 broiler chicks were randomly allocated to six dietary treatments, graded levels of supplementary DL-methionine (+0.7 g/kg), but cystine (0.29%) was equal across groups, lead to levels of 0.59, 0.66, 0.73, 0.8, 0.87, and 0.94% dietary digestible SAAs, with six replicates and ten birds each. All birds were vaccinated with inactivated H9N2/ND and live-ND on days 5 and 11, respectively. Increasing dietary digestible SAAs level improved live body weight (LBW), weight gain (WG), feed efficiency (FE) with linear trends, and improved carcass yield, relative breast weight (RBW), and immune responses with quadratic trends. On day 24, a quadratic increase in blood serum albumin concentration was concomitant with decreasing triglyceride, whole cholesterol, low‐density-lipoprotein cholesterol, creatinine, and alkaline phosphatase concentration with increasing dietary digestible SAAs levels. Based on broken‐line regression models, the LBW, WG, FE, RBW, and immunity against ND and AI vaccination were optimised when dietary digestible SAAs levels were 0.73, 0.69, 0.78, 0.86, 0.73, and 0.72%, respectively. It is concluded, the digestible SAAs requirements of broilers vary according to what production parameter is taken considered for optimisation. The best grower diet digestible SAAs concentration achieved 0.86% for support performance, breast yield, and immune function.

• Highlights

• The present data highlight that a better breast meat yield could be obtained by supplementing DL-Met, which raised dietary digestible sulphur amino acids level to 0.86%.

摘要

本研究旨在确定种植者日粮 (d11-24) 可消化含硫氨基酸 (SAA) 水平对肉鸡性能特征、血液代谢物和对新城疫 (ND) 和禽流感 (AI) 疫苗接种的免疫反应的影响鸡。此外，可消化 SAA 的需求量是根据营养剂量反应数据确定的。总共 360 只 11 日龄雄性 Ross-308 肉鸡被随机分配到六种日粮处理，分级补充 DL-蛋氨酸水平 (+0.7 g/kg)，但胱氨酸 (0.29%) 各组相同，导致 0.59、0.66、0.73、0.8、0.87 和 0.94% 的膳食可消化 SAA 水平，六个重复，每个重复 10 只鸡。所有禽类分别在第 5 天和第 11 天接种灭活 H9N2/ND 和活 ND。增加日粮可消化 SAA 水平可改善活体重 (LBW)、增重 (WG)、饲料效率 (FE)，呈线性趋势，并改善胴体产量、相对乳房重量 (RBW) 和呈二次趋势的免疫反应。在第 24 天，血清白蛋白浓度呈二次增加，同时甘油三酯、全胆固醇、低密度脂蛋白胆固醇、肌酐和碱性磷酸酶浓度随着膳食可消化 SAA 水平的增加而降低。基于折线回归模型，当日粮可消化 SAA 水平分别为 0.73、0.69、0.78、0.86、0.73 和 0.72% 时，LBW、WG、FE、RBW 以及对 ND 和 AI 疫苗接种的免疫力得到优化。结论是，肉鸡的可消化 SAA 要求根据考虑优化的生产参数而有所不同。在支持性能、乳房产量和免疫功能方面，最佳种植者日粮可消化 SAA 浓度达到 0.86%。

• 强调

• 目前的数据强调，通过补充 DL-Met 可以获得更好的胸肉产量，将日粮可消化硫氨基酸水平提高到 0.86%。