4~6月龄杜湖羊杂交 F1代母羔净蛋白质需要量

摘要

This study was conducted to investigate the protein metabolism rules and determine the net protein requirement of Dorper and Hu crossbred F1 ewe lambs aged 4 to 6 months. Forty two four-month-old Dorper and Hu crossbred F1 ewe lambs [(35.68±1.68) kg] were used, comparative slaughter trail (n=30) and di-gestive and metabolic trail ( n=12) were conducted, and factorial method was used to explore the method of predicting net protein requirement for maintenance and growth. Comparative slaughter trail:on day 1 of experi-mental period, six ewes were randomly chosen and killed ( slaughter batch A, n=6) , the rest 24 ewes were divided into 3 groups, which were ad libitum ( AL) group ( n=12) , low-restricted ( LR) group ( n=6) and high-restricted group ( HR, n=6) . When the average body weight ( BW) of ewes in AL group reached 42 kg, six from twelve ewes in AL group were chosen and killed ( slaughter batch B, n=6) , when the rest 6 ewes in AL group reached 50 kg of average BW, ewes in AL, LR and HR groups were killed as slaughter batches C, D and E ( n=6) , respectively. Digestive and metabolic trail:twelve ewes were divided into three groups ( n=4) the same as comparative slaughter trial. The trial included 7 days for adaptation and 5 days for formal trial. The results showed as follows:endogenous nitrogen loss of Dorper and Hu crossbred F1 ewe lambs aged 4 to 6 months was 261 mg/kg SBW0.75( SBW=shrunk BW) , and it corresponded to net protein for maintenance of 1.63 g/kg SBW0.75. Ewes with 35 to 50 kg BW and ADG ranging from 200 to 300 g/d had net protein re-quirement for growth from 9.83 to 25.08 g/d. In conclusion, models for predicting net protein requirements for maintenance and growth of Dorper and Hu crossbred F1 ewe lambs are set in the experiment using retained ni-trogen and nitrogen intake, and body protein content and empty BW, respectively.%本试验旨在探讨杜泊羊×湖羊(杜湖)杂交F1代母羔羊在4~6月龄生长阶段的蛋白质代谢规律的同时确定其净蛋白质需要量。选取4月龄左右湖羊杂交 F1代母羔[(35.68±1.68) kg]42只,结合比较屠宰试验(30只)和消化代谢试验(12只),利用析因法探讨预测维持和生长净蛋白质需要量的方法。比较屠宰试验：正试期第1天随机挑选6只母羔进行屠宰(A屠宰批次,n=6),其余24只羊随机分为自由采食( AL)组( n=12)、低限饲( LR)组( n=6)和高限饲(HR)组(n=6)3组,当AL组羊均重达42 kg时,选取6只进行屠宰(B屠宰批次,n=6),待其余自由采食组羊均重达50 kg时,将AL组、LR组和HR组羊屠宰,分别作为C、D和E屠宰批次( n=6)。消化代谢试验：将12只羊按照比较屠宰试验的设计,分3组( n=4)进行饲喂。预试期7 d,正试期5 d。结果表明：4~6月龄杜湖杂交 F1代母羔的内源性氮损失量为261 mg/kg SBW0.75(SBW为宰前活重),换算为维持净蛋白质需要量为1.63 g/kg SBW0.75。该品种肉羊在35~50 kg体重阶段,平均日增重为100~300 g/d的生长净蛋白质需要量为9.83~25.08 g/d。本试验建立了利用氮沉积量与氮摄入量估测4~6月龄杜湖杂交F1代母羔维持净蛋白质需要量的模型以及体蛋白质含量与排空体重估测生长蛋白质需要量的模型。