Abstract This experiment was conducted to evaluate the effects of dietary digestible sulphur amino acids (DSAAs) level on growth performance, blood metabolites, and liver functional enzymes of broilers during 1–11 days of age. Additionally, DSAAs requirement was determined from dose nutrient response data. A total of 432 1‐day‐old male Ross 308 broilers were allocated to six dietary treatments, graded levels of supplementary DL-Met (+0.8 g/kg per level) while Cys was equal across groups, led to levels of 0.62, 0.70, 0.78, 0.86, 0.94 and 10.2% DSAAs, with six replicates and 12 birds each. Increasing levels of dietary DSAAs enhanced live body weight (LBW), weight gain (WG), feed efficiency (FE), European Production Efficiency Factor (EPEF), and relative breast weight (RBW), although there was no effect on feed intake. At the end of the starter period, a linear increase in blood serum total protein and albumin concentration was concomitant with decreasing in triglyceride, whole cholesterol, high‐density lipoprotein, low‐density lipoprotein, creatinine, and aspartate aminotransferase concentration when dietary DSAAs level was increased. The DSAAs requirements estimated by linear broken-line (LBL) fit model to optimise LBW, WG, FE, EPEF and RBW were 0.80, 0.81, 0.93, 0.95 and 0.93%, although the estimated values by the quadratic broken line fit model were 14.32, 19.93, 16.85, 23.68 and 5.79% higher than those, respectively. It is concluded, a minimum of 0.95% DSAAs concentration in broiler starter diet is suggested to optimise growth performance. Estimation of DSAAs requirement depended on what production parameter and regression model are taken considered for optimisation. Highlights A minimum of 0.95% digestible sulphur amino acids level is suggested in the broiler starter diet to optimise growth performance.

中文翻译：

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日粮可消化硫氨基酸水平对1-11日龄肉鸡生长性能、血液代谢物和肝功能酶的影响

摘要 本试验旨在评估日粮可消化硫氨基酸 (DSAA) 水平对肉鸡 1-11 日龄生长性能、血液代谢物和肝功能酶的影响。此外，DSAAs 要求是根据剂量营养反应数据确定的。总共 432 只 1 日龄雄性 Ross 308 肉鸡被分配到六种日粮处理中，补充 DL-Met 的分级水平（每级 +0.8 g/kg）而 Cys 在各组中相等，导致水平为 0.62、0.70 、0.78、0.86、0.94 和 10.2% DSAA，6 个重复，每个重复 12 只鸟。增加日粮 DSAA 水平可提高活体重 (LBW)、增重 (WG)、饲料效率 (FE)、欧洲生产效率因子 (EPEF) 和相对乳房重量 (RBW)，但对采食量没有影响。在开始阶段结束时，当日粮 DSAAs 水平为 10 时，血清总蛋白和白蛋白浓度线性增加，同时甘油三酯、全胆固醇、高密度脂蛋白、低密度脂蛋白、肌酐和天冬氨酸转氨酶浓度降低。增加。通过线性折线 (LBL) 拟合模型估计的用于优化 LBW、WG、FE、EPEF 和 RBW 的 DSAA 要求为 0.80、0.81、0.93、0.95 和 0.93%，尽管二次折线拟合模型的估计值为 14.32 、19.93、16.85、23.68 和 5.79%，分别比那些高。得出的结论是，建议肉鸡起始日粮中最低浓度为 0.95% 的 DSAA 以优化生长性能。DSAA 需求的估计取决于考虑采用什么生产参数和回归模型进行优化。亮点建议在肉鸡开食料中至少含有 0.95% 的可消化硫氨基酸水平，以优化生长性能。