育肥牛在限饲期间日粮粗蛋白浓度对生产性能、胴体特性及骨骼肌蛋白质周转的影响。
Effects of dietary crude protein concentration during periods of feed restriction on performance, carcass characteristics, and skeletal muscle protein turnover in feedlot steers.
作者信息
Rossi J E, Loerch S C, Keller H L, Willett L B
机构信息
Department of Animal Sciences, Ohio Agricultural Research and Development Center and The Ohio State University, Wooster 44691, USA.
出版信息
J Anim Sci. 2001 Dec;79(12):3148-57. doi: 10.2527/2001.79123148x.
In Exp. 1, 36 individually penned steers (initial BW = 294 +/- 3.8 kg) were used to determine effects of dietary CP percentage and programming gain on performance and carcass characteristics. Steers were fed to achieve a predicted gain of 1.13 kg/d for the first 84 kg of gain and 1.36 kg/d for the next 124 kg of gain and were offered feed for ad libitum consumption for the final 58 kg of gain before slaughter. In these three phases of growth, steers were fed diets, sequentially, with the following CP percentages: HHH (16, 13.5, and 12.5%), LHH (9, 13.5, and 13%), or LLL (9, 9, and 9%). When predicted gain was 1.13 kg/d, ADG was greater (P < 0.01) for steers in the HHH (1.09 kg/d) vs LHH and LLL (0.83 kg/d) systems. When predicted gain was 1.36 kg/d, ADG and gain efficiency were greatest (P < 0.01) for steers in the LHH system. Overall ADG and gain efficiency were greater (P < 0.01) for steers in the HHH (1.46 kg/d, 0.194) and LHH systems (1.38 kg/d, 0.190), compared with steers in the LLL (1.21 kg/d and 0.166) system. Carcass fat thickness was lower for steers in the LHH (0.74 cm) system than for steers in the LLL system (1.09 cm). In Exp. 2, 18 individually penned steers (initial BW = 225 +/- 5.8 kg) were either offered a 13% CP diet for ad libitum intake (AL) throughout the 134-d experiment or fed a high- (16% CP; PI-HH) or low- (10% CP; PI-LH) CP diet and fed to achieve a predicted gain of 1.13 kg/d for the first 85 d of the experiment. Steers in the PI-HH and PI-LH feeding regimens were then offered a 13% CP diet for ad libitum consumption from d 86 to 134. Fractional protein accretion rate was greater (P < 0.01) for steers in the PI-HH and PI-LH feeding regimens than for steers in the AL regimen at d 92, 106, and 120. Fractional breakdown and synthesis rates were not affected (P = 0.63) by feeding regimen. Increased ADG and gain efficiency of steers during compensatory growth periods may in part be due to greater fractional accretion rates of skeletal muscle protein.
在实验1中，选用36头单独圈养的阉牛（初始体重=294±3.8千克）来确定日粮粗蛋白（CP）百分比和规划增重对生产性能及胴体特性的影响。阉牛在前84千克增重阶段按预计日增重1.13千克/天饲喂，接下来124千克增重阶段按1.36千克/天饲喂，在屠宰前最后58千克增重阶段自由采食。在这三个生长阶段，阉牛依次被饲喂以下CP百分比的日粮：HHH（16%、13.5%和12.5%）、LHH（9%、13.5%和13%）或LLL（9%、9%和9%）。当预计日增重为1.13千克/天时，HHH组阉牛的平均日增重（ADG）（1.09千克/天）高于LHH组和LLL组（0.83千克/天）（P<0.01）。当预计日增重为1.36千克/天时，LHH组阉牛的ADG和增重效率最高（P<0.01）。与LLL组（1.21千克/天和0.166）相比，HHH组（1.46千克/天，0.194）和LHH组（1.38千克/天，0.190）阉牛的总体ADG和增重效率更高（P<0.01）。LHH组（0.74厘米）阉牛的胴体脂肪厚度低于LLL组（1.09厘米）。在实验2中，18头单独圈养的阉牛（初始体重=225±5.8千克）在为期134天的实验中，要么自由采食13%CP日粮（AL），要么先饲喂高CP日粮（16%CP；PI-HH）或低CP日粮（10%CP；PI-LH），并在实验的前85天按预计日增重1.13千克/天饲喂。然后，PI-HH组和PI-LH组的阉牛从第86天至134天自由采食13%CP日粮。在第92天、106天和120天，PI-HH组和PI-LH组阉牛的蛋白质净增值率高于AL组（P<0.01）。饲喂方式对蛋白质分解率和合成率没有影响（P=0.63）。阉牛在补偿生长阶段ADG和增重效率的提高可能部分归因于骨骼肌蛋白更高的净增值率。
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