McNamara J P, Brekke C J, Jones R W, Dalrymple R H
Washington State University, Pullman 99164-6320.
J Anim Sci. 1991 Jun;69(6):2273-81. doi: 10.2527/1991.6962273x.
The efficacy of recombinantly derived porcine somatotropin (rpST) in improving the performance and carcass characteristics of heavyweight finishing pigs was determined. In Study 1, 36 pigs were killed for determination of initial carcass composition at 102 kg, and 36 pigs each were given 0, 1.5, 3, 6, or 9 mg of rpST/d from 102 to 136 kg live weight. Corn-soybean meal diets fed contained 19.8% CP and greater than 1% lysine. Study 2 tested the effects of 3 mg/d on pigs for 4 wk from 84 kg BW fed a corn-soybean meal or a triticale-barley-peas diet. Performance variables (ADG, average daily feed intake [ADFI], and feed efficiency [FE]) were measured weekly. Treatment with rpST increased (P less than .01) ADG and FE and decreased (P less than .01) ADFI in both studies. In Study 1, leaf fat, backfat thickness, belly thickness, and carcass fat were all decreased (P less than .01) linearly by rpST. Loin eye area (LEA), total trimmed lean, and total protein content were increased quadratically (P less than .01). At the 3-mg dose, ADFI, ADG, and FE were 87, 130, and 137% of control, and LEA, backfat, total protein gain, and total fat gain were 107, 80, 136, and 52% of control. Loin eye area was not increased (P greater than .05) in the pigs in Study 2; however, backfat thickness was reduced 16% by rpST (P less than .01). The effects of rpST were the same on both dietary regimens (P greater than .05). These studies demonstrate the effectiveness of rpST in increasing ADG and carcass leanness and improving FE in heavyweight pigs and in pigs fed alternative feedstuffs.
测定了重组猪生长激素（rpST）对体重较大的育肥猪生产性能和胴体特性的影响。在研究1中，36头猪在体重102千克时被宰杀以测定初始胴体组成，另外36头猪在体重从102千克增长到136千克期间，分别每日给予0、1.5、3、6或9毫克的rpST。所饲喂的玉米-豆粕型日粮含19.8%的粗蛋白和超过1%的赖氨酸。研究2测试了从84千克体重开始，连续4周每日3毫克rpST对饲喂玉米-豆粕型日粮或小黑麦-大麦-豌豆日粮的猪的影响。每周测量生产性能变量（平均日增重[ADG]、平均日采食量[ADFI]和饲料效率[FE]）。在两项研究中，rpST处理均使ADG和FE提高（P＜0.01），使ADFI降低（P＜0.01）。在研究1中，rpST使叶脂肪、背膘厚度、腹部厚度和胴体脂肪均呈线性降低（P＜0.01）。眼肌面积（LEA）、总净瘦肉量和总蛋白含量呈二次曲线增加（P＜0.01）。在3毫克剂量时，ADFI、ADG和FE分别为对照的87%、130%和137%，LEA、背膘、总蛋白增加量和总脂肪增加量分别为对照的107%、80%、136%和52%。在研究2的猪中，眼肌面积没有增加（P＞0.05）；然而，rpST使背膘厚度降低了16%（P＜0.01）。rpST对两种日粮方案的影响相同（P＞0.05）。这些研究证明了rpST在提高体重较大的猪以及饲喂替代饲料原料的猪的ADG和胴体瘦肉率并改善FE方面的有效性。
