Caperna T J, Steele N C, Komarek D R, McMurtry J P, Rosebrough R W, Solomon M B, Mitchell A D
U.S. Department of Agriculture, Beltsville, MD 20705.
J Anim Sci. 1990 Dec;68(12):4243-52. doi: 10.2527/1990.68124243x.
The influence of dietary protein and recombinant porcine somatotropin (rpST) administration on growth and body composition was investigated in barrows. Ten groups of six pigs starting at 30 kg were restrictively fed (approximately 80% of ad libitum) one of five diets containing 11, 15, 19, 23 or 27% protein. Diets contained skim milk (12%). Soybean meal diluted with cornstarch was used as the supplemental source of dietary protein. Diets were isocaloric (3.8 Mcal DE/kg) and all contained the same amount of lysine (18 to 20 g/kg). Thirty pigs were treated daily with rpST (100 micrograms/kg) by i.m. injection; the remaining pigs were treated with sterile diluent (control) for 42 d. Growth rate was greater in rpST-treated pigs at all levels of protein intake; however, the magnitude of the response to rpST treatment was lowest among pigs fed the diet containing 11% protein. Feed:gain ratio, backfat depth and carcass fat content were decreased in rpST-treated pigs compared to respective controls. Additionally, the concentration of carcass fat decreased concomitantly with an increase in dietary protein intake. Concentration of carcass protein increased linearly as dietary protein increased in control and rpST-treated pigs. In contrast, treatment with rpST was associated with an increased visceral mass; the concentration of protein and fat in the viscera was influenced by protein intake but not by rpST. These results, characterized by few treatment interactions, suggest that when energy intake is kept constant and appropriately fed pigs serve as controls, dietary protein and rpST influence growth and body composition by independent mechanisms.(ABSTRACT TRUNCATED AT 250 WORDS)
研究了日粮蛋白质和重组猪生长激素（rpST）对阉公猪生长和体组成的影响。10组猪，每组6头，初始体重30 kg，分别限饲（约为自由采食的80%）5种日粮中的一种，这5种日粮的蛋白质含量分别为11%、15%、19%、23%或27%。日粮中含有脱脂乳（12%）。用玉米淀粉稀释的豆粕作为日粮蛋白质的补充来源。日粮能量相等（3.8 Mcal DE/kg），且所有日粮赖氨酸含量相同（18至20 g/kg）。30头猪每天通过肌肉注射rpST（100微克/千克）进行处理；其余猪用无菌稀释剂处理（对照），持续42天。在所有蛋白质摄入水平下，rpST处理的猪生长速度更快；然而，在采食含11%蛋白质日粮的猪中，对rpST处理的反应程度最低。与各自的对照组相比，rpST处理的猪料重比、背膘厚度和胴体脂肪含量降低。此外，胴体脂肪浓度随着日粮蛋白质摄入量的增加而降低。在对照猪和rpST处理的猪中，胴体蛋白质浓度随着日粮蛋白质的增加呈线性增加。相反，rpST处理与内脏质量增加有关；内脏中蛋白质和脂肪的浓度受蛋白质摄入量影响，但不受rpST影响。这些结果显示处理间相互作用较少，表明当能量摄入量保持恒定且以适当饲喂的猪作为对照时，日粮蛋白质和rpST通过独立机制影响生长和体组成。（摘要截短至250词）
