本试验旨在研究1 ～21日龄雌性肉仔鸡表观回肠可消化色氨酸需要量及饲粮色氨酸水平对肉仔鸡肉品质、抗氧化指标和免疫指标的影响.试验选取480只1日龄雌性商品代肉雏鸡,随机分成5个处理,每个处理8个重复,每个重复12只鸡.采用含0.170％色氨酸的玉米-豆粕-玉米蛋白粉型基础饲粮,分别在其中添加0、0.021％、0.042％、0.063％和0.084％晶体L-色氨酸,使饲粮色氨酸水平分别为0.170％、0.191％、0.213％、0.234％和0.248％.测定1～ 21日龄肉仔鸡生产性能、胸肌品质、抗氧化指标、免疫指标和21～25日龄肉仔鸡氨基酸表观消化率和表观回肠消化率.结果表明:饲粮色氨酸水平显著影响1 ～21日龄肉仔鸡采食量及增重(P＜0.05),采食量及增重与饲粮表观回肠可消化色氨酸水平呈现二次曲线关系(P＜0.05).1～21日龄肉仔鸡获得最大增重的饲粮表观回肠可消化色氨酸水平为0.176％,表观回肠可消化色氨酸摄入量为68.15 mg/d.与饲粮色氨酸水平0.170％相比,饲粮色氨酸水平0.213％及0.248％可显著降低肉仔鸡胸肌丙二醛含量、肝脏总超氧化物歧化酶活性和血清谷丙转氨酶活性(P＜0.05),饲粮色氨酸水平0.248％可显著提高肉仔鸡屠宰后45min胸肌pH、肠道总分泌型免疫球蛋白A浓度及血清总免疫球蛋白A浓度(P＜0.05).由此可知,1 ～21日龄雌性肉仔鸡获得最大增重的表观回肠可消化色氨酸需要量为0.176％ (68.15 mg/d).提高饲粮色氨酸水平可减轻肉仔鸡组织细胞脂质过氧化损伤,降低屠宰后肉仔鸡胸肌酸度,改善肉仔鸡肠道黏膜免疫和体液免疫能力.%This study was conducted to determine apparent ileal digestible tryptophan (Trp) requirement of female broilers aged 1 to 21 days and effects of dietary tryptophan level on meat quality, antioxidant and immune indices. A total of 480 one-day-old Cobb female broilers were randomly allocated into 5 treatments with 8 replicates per treatment and 12 broilers per replicate. Corn-soybean meal-corn gluten meal diets containing 0.170% , 0. 191% , 0.213% , 0.234% and 0. 248% Trp (0. 170% basis Trp and 0, 0. 021% , 0. 042% , 0.063% and0.084% crystal L-Trp, respectively) were provided. Growth performance, meat quality, antioxidant and immune indices of broilers aged 21 days were determined. Apparent digestibility and apparent ileal digestibility of amino acids for broilers aged 21 to 25 days were measured by indicator method. The results showed as follows: dietary Trp level significantly affected feed intake and weight gain of broilers aged 1 to 21 days (P <0. 05). There was a quadratic relationship between feed intake or weight gain and dietary apparent ileal digestible Trp level (F<0.05). Based on the response in weight gain, apparent ileal digestible Trp requirement of female broilers aged 1 to 21 days was 0. 176% ( apparent ileal digestible Trp intake was 68.15 mg/d). Malondialdehyde (MDA) content in breast muscle, total superoxide dismutase (T-SOD) activity in liver and glutamate-pyruvate transaminase activity in serum of broilers fed the diet containing 0. 213% or 0. 248% Trp were significantly decreased compared with those fed the diet containing 0. 170% Trp (P < 0.05). Breast muscle pH value at 45 min post-slaughter, intestinal total secretary immunoglobulin A ( slgA) and serum total IgA concentrations of broilers fed the diet containing 0. 248% Trp were significantly improved compared with those fed the diet containing 0. 170% Trp (P <0. 05) . The current study suggests that female broilers aged 1 to 21 days need 0. 176% (68. 15 mg/d) apparent ileal digestible Trp to get the maximum weight gain. Increasing dietary Trp level can alleviate lipid peroxidation and breast muscle acidity post-slaughter, and improve intestinal mucosal immunity and humoral immunity of broilers. [ Chinese Journal of Animal Nutrition, 2012, 24 (9) : 1664-1673 ]
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