Tuitoek K, Young L G, de Lange C F, Kerr B J
Department of Animal and Poultry Science, University of Guelph, ON, Canada.
J Anim Sci. 1997 Jun;75(6):1575-83. doi: 10.2527/1997.7561575x.
Seventy-two gilts were used to determine the effect of reducing excess amino acid intake on growing-finishing pig performance. Separate diets were formulated for the growing (20 to 55 kg BW) and finishing (55 to 100 kg BW) periods. For each period, three diets were formulated that varied in total crude protein level and contained similar levels of digestible ideal protein. Crystalline amino acids were added to the low protein diets to overcome potential deficiencies. The grower diets contained .66% apparent ileal digestible lysine and contained 16.6, 15.0, and 13.0% CP, respectively; for the finisher diets, these values were .55% digestible lysine and 14.2, 12.8, and 11.0% CP, respectively. Amino acid analyses and a separate digestibility trial were conducted to confirm digestible amino acid levels in the dietary ingredients. During the growing and the overall growing-finishing period, daily gain, feed intake, and gain:feed were not affected (P > .10) by dietary treatment. Daily gain tended to be lower (P = .06) and gain:feed was poorer (P < .05) for pigs fed the 11.0% CP diet during the finishing phase. Although backfat thickness tended to be greater (P = .07) for pigs fed the lower-CP diet, estimated carcass lean yield was not affected (P > .10) by dietary treatment. Results of this study show that dietary CP can be reduced to 13% in the growing and 12.8% in the finishing diets of pigs as long as crystalline amino acids are added to match the apparent ileal digestible amino acid ratios in an assumed ideal protein.
选用72头后备母猪来测定减少过量氨基酸摄入量对生长育肥猪生产性能的影响。针对生长阶段（体重20至55千克）和育肥阶段（体重55至100千克）分别配制了不同的日粮。每个阶段都配制了三种日粮，其粗蛋白总量不同，但可消化理想蛋白水平相近。向低蛋白日粮中添加了结晶氨基酸以克服潜在的不足。生长猪日粮含0.66%的表观回肠可消化赖氨酸，粗蛋白含量分别为16.6%、15.0%和13.0%；育肥猪日粮的这些值分别为0.55%可消化赖氨酸和14.2%、12.8%和11.0%粗蛋白。进行了氨基酸分析和一项单独的消化率试验，以确认日粮成分中的可消化氨基酸水平。在生长阶段以及整个生长育肥期，日粮处理对日增重、采食量和料重比均无影响（P>.10）。在育肥阶段，饲喂11.0%粗蛋白日粮的猪日增重趋于降低（P = 0.06），料重比也较差（P < 0.05）。尽管饲喂低粗蛋白日粮的猪背膘厚度趋于更厚（P = 0.07），但日粮处理对估计的胴体瘦肉率没有影响（P>.10）。本研究结果表明，只要添加结晶氨基酸以匹配假定理想蛋白中的表观回肠可消化氨基酸比例，生长猪日粮中的粗蛋白可降至13%，育肥猪日粮中的粗蛋白可降至12.8%。
