饲粮蛋氨酸水平对43～63日龄黄羽肉鸡生长性能、胴体品质、羽毛蛋白质沉积和肉质的影响

摘要

This experiment was conducted to study the effects of dietary methionine (Met) levels on growth performance, carcass quality, feather and carcass protein retention and meat quality, and to determine the Met requirements in yellow-feathered broiler chickens aged from 43 to 63 days based on quadratic regression model.One thousand and six hundred 43-day-old Lingnan yellow-feathered broiler chickens were divided into 10 groups (5 groups each gender) with 4 replicates per group and 40 chickens in each replicate according to body weight and gender. Five dietary treatments were compared in a 5 × 2 factorial arrangement with five dietary Met levels (0.25％ , 0.30％ , 0.35％, 0.40％ and 0.45％ ) and two genders. The results showed that with the increasing of Met supplementation levels, daily total Met and true digestible Met intake of female and male birds were increased linearly or quadratically ( P ＜ 0.05 ), feed/gain of male chickens was decreased quadratically ( P ＜0.05 ), and eviscerated percentage and breast muscle percentage of both male and female chickens were increased quadratically (P ＜0.05 or 0. 10). Compared with the diets with 0.25％ and 0.35％ Met, diets supplemented with 0.40％ and 0.45％ Met decreased the dressing percentage of male chickens (P ＜ 0.05). Compared with the diet with 0.25％ Met, diets supplemented with 0.30％ and 0.45％ Met decreased the abdominal fat weight and percentage of male chickens (P ＜0.05), and diets supplemented with 0.35％, 0.40％ or 0.45％ Met significantly increased the DM content and protein retention in the feather, and feather or carcass protein content of female chickens (P ＜ 0.05). In conclusion, appropriate Met can enhance the feed conversion rate, improve the carcass quality and promote the feather growth of yellow-feathered broiler chickens. However, excessive Met has a negative effect on carcass quality. The estimated Met requirements for female yellow-feathered broiler chickens to gain maximum eviscerated percentage or breast muscle percentage are 0. 269％ and 0.330％ (total Met), and 0. 246％ and 0.307％ ( digestible Met), respectively. The Met requirements for males yellow-feathered broiler chickens to gain maximum eviscerated percentage, breast muscle percentage and minimum feed/gain are 0. 353％, 0.289％ and 0.313％ (total Met), and 0.330％, 0.266％ and 0. 290％ ( digestible Met), respectively. [ Chinese Journal of Animal Nutrition,2011,23 (2) :210-218]%本试验旨在研究饲粮中添加不同水平蛋氨酸对43～63日龄黄羽肉鸡生长性能、胴体品质、胴体和羽毛蛋白质沉积以及肉质的影响,并根据二次回归模型估测其蛋氨酸需要量.选用43日龄岭南黄鸡1 600只,按性别和体重分成10组(公母各5组),每组4个重复,每个重复40只.采用5×2(饲粮蛋氨酸水平×性别)两因子试验设计,饲粮蛋氨酸水平分别为0.25%、0.30%、0.35%、0.40%和0.45%.结果表明,随着饲粮蛋氨酸水平提高,公、母鸡每日总蛋氨酸和真可消化蛋氨酸摄入量呈线性或二次曲线升高(P＜0.05),公鸡料重比呈二次曲线降低(P＜0.05),公、母鸡全净膛率呈先升后降二次曲线变化(P＜0.05),胸肌率呈二次曲线升高(P＜0.05或P＜0.10).0.40%和0.45%蛋氨酸水平组公鸡屠宰率低于0.25%和0.35%蛋氨酸水平组,0.30%和0.45%蛋氨酸水平组公鸡腹脂率和腹脂重低于0.25%蛋氨酸水平组(P＜0.05).与0.25%蛋氨酸水平组相比,0.35%、0.40%或0.45%蛋氨酸水平组显著提高母鸡羽毛中干物质含量和蛋白质沉积、胴体蛋白质含量或羽毛蛋白质含量(P＜0.05).由此可见,饲粮中适量添加蛋氨酸提高了黄羽肉鸡饲料利用率,改善了胴体品质,促进了母鸡羽毛蛋白质沉积,但添加量过高会对胴体品质产生不利影响.估测43～63日龄母鸡获得最大全净膛率和胸肌率95%处的总蛋氨酸需要量为0.269%和0.330%,可消化蛋氨酸需要量为0.246%和0.307%;公鸡获得最低料重比、最大全净膛率和胸肌率95%处的总蛋氨酸需要量为0.353%、0.289%和0.313%,可消化蛋氨酸需要量为0.330%、0.266%和0.290%.