Krick B J, Boyd R D, Roneker K R, Beermann D H, Bauman D E, Ross D A, Meisinger D J
Department of Animal Science, Cornell University, Ithaca, NY 14853.
J Nutr. 1993 Nov;123(11):1913-22. doi: 10.1093/jn/123.11.1913.
This study was conducted to determine the effects of exogenous porcine somatotropin (pST) on the dietary lysine requirement and efficiency of absorbed lysine utilization for pigs during the 20- to 60-kg phase of growth. Seventy-two crossbred pigs (20 +/- 0.7 kg body wt) received daily intramuscular injections of either excipient (0 dose) or pST (150 micrograms/kg body wt) and were fed diets in which protein and lysine concentrations ranged from 6.4 to 23.5 g/100 g diet and from 0.40 to 1.48 g/100 g diet, respectively. Nutrient density was altered to compensate for reduced feed intake with pST, but diets were approximately isocaloric. Rate and efficiency of gain and whole-body protein accretion rate exhibited a dose-response improvement (P < 0.01) to increases in dietary protein for both excipient and pST-treated pigs. Pigs receiving pST grew more rapidly and more efficiently than control counterparts (P < 0.01). Treatment with pST improved the rate of protein accretion (P < 0.01) at all but the lowest level of dietary protein. The net lysine utilization for lysine accretion and maintenance was 0.46 for control pigs and 0.57 for pigs receiving pST, a 24% improvement in the efficiency. Thus, treatment with pST increased the maximum rate of protein accretion as well as the partial efficiency with which dietary lysine is used for protein accretion. Consequently, only a 9% increase in dietary lysine was required to maximize protein deposition in pST-treated pigs, because the metabolic efficiency of lysine utilization was improved.
本研究旨在确定外源性猪生长激素（pST）对20至60千克生长阶段猪的日粮赖氨酸需要量以及吸收赖氨酸利用效率的影响。72头杂种猪（体重20±0.7千克）每天分别接受赋形剂（0剂量）或pST（150微克/千克体重）的肌肉注射，并饲喂蛋白质和赖氨酸浓度分别为6.4至23.5克/100克日粮和0.40至1.48克/100克日粮的日粮。通过改变营养密度来补偿pST导致的采食量减少，但日粮能量大致相等。对于接受赋形剂和pST处理的猪，生长速度、生长效率和全身蛋白质沉积率均随日粮蛋白质增加呈剂量反应性提高（P<0.01）。接受pST处理的猪比对照猪生长更快、更有效率（P<0.01）。除日粮蛋白质最低水平外，pST处理提高了所有水平的蛋白质沉积率（P<0.01）。对照猪用于赖氨酸沉积和维持的净赖氨酸利用率为0.46，接受pST处理的猪为0.57，效率提高了24%。因此，pST处理提高了蛋白质沉积的最大速率以及日粮赖氨酸用于蛋白质沉积的部分效率。因此，pST处理的猪只需将日粮赖氨酸增加9%就能使蛋白质沉积最大化，因为赖氨酸利用的代谢效率提高了。
