Six feeding trials were conducted to determine the optimum intake of standardized ileal digestible (SID) tryptophan of male and female broiler chickens in the starter (0 to 14 d), grower (14 to 28 d), and finisher (28 to 42 d) phases. In each trial, 640 broiler chickens were randomly assigned to 1 of 8 treatments, with 4 replicates of 20 broiler chickens. Diets were formulated by mixing a high and a low protein diet in different proportions, and dietary concentrations of SID Trp ranged 0.56 to 2.94, 0.54 to 2.75, and 0.52 to 2.60 g/kg in the starter, grower, and finisher phases, respectively. Tryptophan intake was regressed against average daily gain (ADG) and feed conversion ratio (FCR) using polynomial regression and broken-line regression model and the model that better fitted data was chosen according to Bayesian information criterion. Broiler chickens responded quadratically to increasing dietary Trp concentration and ADG was maximized at 86, 264, and 441 mg SID Trp/d for male broiler chickens (R² = 0.96; P < 0.01) and at 76.5, 237, and 278 mg SID Trp/d for females (R² = 0.97; P < 0.01) in the starter, grower and finisher phases, respectively. Feed conversion ratio was optimized at 69.9, 247, and 338 mg SID Trp/d for males (R² = 0.91; P < 0.01) and 67.8, 223, and 280 mg SID Trp/d for females (R² = 0.93; P < 0.01) in the starter, grower, and finisher phases, respectively. The optimum SID Trp intake for each sex and phase was determined based on ADG.

进行了六次饲喂试验，以确定在开始阶段（0至14 d），生长阶段（14至28 d）和育成阶段（28至42 d）雄性和雌性肉鸡标准化回肠可消化色氨酸的最佳摄入量阶段。在每个试验中，将640只肉鸡随机分配到8种处理方法中的1种中，每组20只肉鸡进行4次重复。通过在不同比例下混合高蛋白和低蛋白饮食来配制饮食，在开始，生长和育成阶段，SID Trp的饮食浓度分别为0.56至2.94、0.54至2.75和0.52至2.60 g / kg。使用多项式回归和折线回归模型，将色氨酸摄入量与平均日增重（ADG）和饲料转化率（FCR）进行回归，并根据贝叶斯信息准则选择更适合数据的模型。²  = 0.96；P <0.01），并且在开始，成长期和育肥阶段分别为雌性（R ²  = 0.97; P <0.01）的SID Trp / d为76.5、237和278 mg 。男性的饲料转化率被优化为69.9、247和338 mg SID Trp / d（R ²  = 0.91; P <0.01）和女性的饲料转化率被优化为67.8，223和280 mg SID Trp / d（R ²  = 0.93; P <0.01）分别在起步阶段，生长阶段和完成阶段。根据ADG确定每种性别和阶段的最佳SID Trp摄入量。