Nossaman D A, Schinckel A P, Miller L F, Mills S E
Department of Animal Science, Purdue University, West Lafayette, IN 47907.
J Nutr. 1991 Feb;121(2):223-30. doi: 10.1093/jn/121.2.223.
Eighty barrows were used in a 2 x 2 x 4 factorial experiment to examine the effects of genetic line (Hampshire x Yorkshire, H x Y, and Yorkshire x Landrace, Y x L), somatotropin (dose, 0 and 5 mg/d) and energy intake (ad libitum, 93%, 86% and 80%) on growth performance and energy requirements for lean gain over the finishing phase of growth. Four diets were formulated to maintain equal intakes of protein, vitamins and minerals at different energy intakes. Somatotropin increased growth rate 30 to 35% across diets despite an 8 to 12% reduction in ad libitum feed intake. Lean growth rate (kg/d) was increased preferentially by ST in the faster-growing H x Y barrows, which showed a 2.8-fold greater maximum rate increase than the slower-growing Y x L barrows. In control barrows, 10% reductions in energy intake had no effect on lean gain and improved feed/lean gain about 10%. In somatotropin-treated barrows, lean gain was reduced with each energy restriction in H x Y; energy intake had no effect on lean gain in Y x L barrows. Feed/lean gain was improved 22% in Y x L barrows at the lowest energy intake. Data indicate that somatotropin accentuates breed differences in lean gain and energy requirements. Pigs with low lean-growth potential will benefit from restricted feeding, whereas strategies to increase energy intake in pigs with high lean-growth potential may be desirable.
80头公猪用于一项2×2×4析因试验，以研究遗传品系（汉普夏×约克夏，H×Y，以及约克夏×长白，Y×L）、生长激素（剂量，0和5毫克/天）和能量摄入量（自由采食、93%、86%和80%）对育肥阶段生长性能和瘦肉生长能量需求的影响。配制了四种日粮，以在不同能量摄入量下保持蛋白质、维生素和矿物质的摄入量相等。尽管自由采食量减少了8%至12%，但生长激素在所有日粮中均使生长速度提高了30%至35%。在生长较快的H×Y公猪中，生长激素优先提高了瘦肉生长速度（千克/天），其最大生长速度增幅比生长较慢的Y×L公猪高2.8倍。在对照公猪中，能量摄入量减少10%对瘦肉生长没有影响，饲料/瘦肉比提高了约10%。在生长激素处理的公猪中，H×Y公猪每一次能量限制都会使瘦肉生长减少；能量摄入量对Y×L公猪的瘦肉生长没有影响。在最低能量摄入量时，Y×L公猪的饲料/瘦肉比提高了22%。数据表明，生长激素加剧了瘦肉生长和能量需求方面的品种差异。瘦肉生长潜力低的猪将受益于限饲，而对于瘦肉生长潜力高的猪，增加能量摄入量的策略可能是可取的。
