Johnston M E, Nelssen J L, Goodband R D, Kropf D H, Hines R H, Schricker B R
Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506-0201.
J Anim Sci. 1993 Nov;71(11):2986-95. doi: 10.2527/1993.71112986x.
One hundred twenty barrows (initially 59 kg) were used to determine the effects of dietary lysine and porcine somatotropin (pST) on growth performance and carcass characteristics of finishing pigs fed to heavy market weights (127 kg). Pigs were injected daily with either 4 mg of pST or a placebo and fed diets containing either .8, 1.0, 1.2, or 1.4% lysine in a 2 x 4 factorial arrangement. Performance data were collected and evaluated for the weight ranges: 59 to 105, 105 to 127, and 59 to 127 kg. In addition, daily accretion rates of protein (DPA), lipid (DLA), moisture, and ash were determined by slaughtering six randomly selected pigs at the start of the experiment, then one pig per pen when pigs reached mean weights of 105 and 127 kg. Pigs injected with pST had greater (P < .05) ADG than control pigs at all weight ranges. Increased dietary lysine had no effect (P > .20) on ADG during the entire trial (59 to 127 kg). Although control pigs showed no increase in ADG with increasing lysine, ADG of pST-treated pigs tended to increase. This resulted in a pST x lysine interaction (P < .07) for ADG from 59 to 127 kg. Feed consumption decreased (P < .05) in pigs from 59 to 105 kg and 59 to 127 kg with pST treatment and with increasing dietary lysine. Feed conversion (G/F) was improved (P < .01) by pST administration and a tendency for a pST x lysine interaction (P < .12) was observed. At 105 kg, average backfat thickness, kidney fat, longissimus muscle area, and DPA were unaffected by dietary lysine but were improved by pST treatment (P < .01). At a slaughter weight of 127 kg, average backfat thickness decreased and DPA increased (linear, P < .05) with increasing dietary lysine and pST treatment (P < .01). Longissimus muscle area was increased and DLA was decreased (P < .01) by injections of pST but both were unchanged by dietary lysine. These data indicate that growth performance and carcass characteristics at 105 and 127 kg were improved by daily administration of 4 mg of pST. At both slaughter weights, increasing dietary lysine resulted in increased carcass leanness (increased carcass protein and decreased carcass lipid). Although increasing lysine did not improve overall (59 to 127 kg) ADG and feed efficiency, pST-treated pigs showed a greater response to increasing dietary lysine. The data indicate that pST-treated pigs (4 mg/d) require approximately 28 g/d of lysine.
选用120头仔猪（初始体重59千克），研究日粮赖氨酸和猪生长激素（pST）对育肥猪生长性能和胴体特性的影响，育肥猪饲养至上市体重（127千克）。猪只每日注射4毫克pST或安慰剂，并按照2×4析因设计饲喂含0.8%、1.0%、1.2%或1.4%赖氨酸的日粮。收集并评估59至105千克、105至127千克以及59至127千克体重范围内的生产性能数据。此外，通过在试验开始时屠宰6头随机挑选的猪，然后在猪只平均体重达到105千克和127千克时每栏屠宰1头猪，测定蛋白质（DPA）、脂肪（DLA）、水分和灰分的日沉积率。在所有体重范围内，注射pST的猪只平均日增重（ADG）均高于对照猪（P < 0.05）。在整个试验期（59至127千克），日粮赖氨酸增加对ADG无影响（P > 0.20）。虽然对照猪的ADG未随赖氨酸增加而提高，但pST处理的猪只ADG有增加趋势。这导致59至127千克体重阶段ADG存在pST×赖氨酸互作效应（P < 0.07）。pST处理且日粮赖氨酸增加时，59至105千克以及59至127千克体重阶段猪只的采食量下降（P < 0.05）。pST给药改善了饲料转化率（G/F）（P < 0.01），且观察到pST×赖氨酸存在互作趋势（P < 0.12）。在105千克体重时，日粮赖氨酸对平均背膘厚、肾周脂肪、背最长肌面积和DPA无影响，但pST处理改善了这些指标（P < 0.01）。在127千克屠宰体重时，随着日粮赖氨酸增加和pST处理（P < 0.01），平均背膘厚下降，DPA增加（呈线性，P < 0.05）。注射pST使背最长肌面积增加，DLA下降（P < 0.01），但日粮赖氨酸对二者无影响。这些数据表明，每日注射4毫克pST可改善105千克和127千克体重阶段的生长性能和胴体特性。在两个屠宰体重下，日粮赖氨酸增加均导致胴体瘦肉率提高（胴体蛋白质增加，胴体脂肪减少）。虽然增加赖氨酸未改善总体（59至127千克）ADG和饲料效率，但pST处理的猪只对日粮赖氨酸增加的反应更大。数据表明，pST处理的猪只（4毫克/天）大约需要28克/天的赖氨酸。
