Kerr B J, Easter R A
Department of Animal Sciences, University of Illinois, Urbana 61801, USA.
J Anim Sci. 1995 Oct;73(10):3000-8. doi: 10.2527/1995.73103000x.
Two experiments were conducted to determine the effect of feeding reduced CP, amino acid (AA)-supplemented diets on the nitrogen (N) and energy (E) balance of grower pigs. In Exp. 1, 24 barrows (22.2 kg BW) were fed corn-soybean meal (C-SBM) diets containing either 16% CP, 12% CP, or 12% CP supplemented with lysine (LYS), tryptophan (TRP), and threonine (THR). After 6 d of adaptation to the diets and feeding frequency, a 5-d N and E balance trial was conducted. Supplementation of the 12% CP diet with LYS, TRP, and THR improved N retention ( P < .01) but failed to improve N retention to the level attained by pigs fed the 16% CP diet (P < .01). Efficiency of N retention was similar between pigs fed the AA-supplemented 12% CP diet and pigs fed the 16% CP diet (P > .10). Energy retention was increased by AA-supplementation of the 12% CP diet ( P < .10) to a level higher than that of pigs fed the 16% CP diet (P < .01). In Exp. 2, 60 barrows (21.7 kg BW) were fed one of the following diets: 16% CP; 12% CP diet supplemented with indispensable AA (IDAA) to simulate the 16% CP diet; 12% CP supplemented with LYS, TRP, THR, and dispensable AA N (DAAN); 12% CP supplemented with LYS, TRP, and THR; or a 12% CP negative control diet. After 6 d of adaptation to the diets and feeding frequency, a 5-d N and E balance trial was conducted. Nitrogen retention was improved (P < .01) by supplementing the 12% CP diet with LYS, TRP, and THR but remained inferior (P < .01) to that obtained when pigs were fed the other three diets. Pigs fed the 12% CP diet with LYS, TRP, THR, and DAAN supplementation retained less N (P < .07) than pigs fed the 16% CP but retained an amount similar (P > .10) to pigs fed the 12% CP diet with IDAA and DAAN supplementation. Pigs fed the 12% CP diet with LYS, TRP, and THR supplementation exhibited the highest efficiency of N retention (P < .01). Pigs fed the 12% CP diet supplemented with LYS, TRP, THR, and DAAN retained more (P < .01) E than pigs fed the 12% CP diet supplemented with IDAA and DAAN and more (P < .07) E than pigs fed either the 12% CP diet supplemented with LYS, TRP, and THR or the unsupplemented 12% CP diet. Pigs fed the 16% CP diet retained more (P < .06) E than pigs fed the 12% CP diet with IDAA and DAAN supplementation. Although the data show that the efficiency of N retention is greatest when LYS, TRP, and THR are supplemented to the 12% CP diet, maximal N retention is achieved only when the 12% CP diets are supplemented with both the deficient AA and a source of N for dispensable AA synthesis.
进行了两项试验，以确定饲喂低粗蛋白、氨基酸（AA）补充日粮对生长猪氮（N）和能量（E）平衡的影响。在试验1中，给24头公猪（体重22.2千克）饲喂含16%粗蛋白、12%粗蛋白或添加赖氨酸（LYS）、色氨酸（TRP）和苏氨酸（THR）的12%粗蛋白的玉米-豆粕（C-SBM）日粮。在适应日粮和饲喂频率6天后，进行为期5天的氮和能量平衡试验。给12%粗蛋白日粮补充LYS、TRP和THR可提高氮保留率（P<0.01），但未能将氮保留率提高到饲喂16%粗蛋白日粮的猪所达到的水平（P<0.01）。补充氨基酸的12%粗蛋白日粮的猪与饲喂16%粗蛋白日粮的猪的氮保留效率相似（P>0.10）。给12%粗蛋白日粮补充氨基酸可提高能量保留率（P<0.10），使其高于饲喂16%粗蛋白日粮的猪（P<0.01）。在试验2中，给60头公猪（体重21.7千克）饲喂以下日粮之一：16%粗蛋白；补充必需氨基酸（IDAA）以模拟16%粗蛋白日粮的12%粗蛋白日粮；补充LYS、TRP、THR和非必需氨基酸氮（DAAN）的12%粗蛋白日粮；补充LYS、TRP和THR的12%粗蛋白日粮；或12%粗蛋白阴性对照日粮。在适应日粮和饲喂频率6天后，进行为期5天的氮和能量平衡试验。给12%粗蛋白日粮补充LYS、TRP和THR可提高氮保留率（P<0.01），但仍低于饲喂其他三种日粮的猪（P<0.01）。补充LYS、TRP、THR和DAAN的12%粗蛋白日粮的猪比饲喂16%粗蛋白日粮的猪保留的氮少（P<0.07），但与补充IDAA和DAAN的12%粗蛋白日粮的猪保留的氮量相似（P>0.10）。补充LYS、TRP和THR的12%粗蛋白日粮的猪表现出最高的氮保留效率（P<0.01）。补充LYS、TRP、THR和DAAN的12%粗蛋白日粮的猪比补充IDAA和DAAN的12%粗蛋白日粮的猪保留更多（P<0.01）的能量，比补充LYS、TRP和THR的12%粗蛋白日粮或未补充的12%粗蛋白日粮的猪保留更多（P<0.07）的能量。饲喂16%粗蛋白日粮的猪比补充IDAA和DAAN的12%粗蛋白日粮的猪保留更多（P<0.06）的能量。虽然数据表明，给12%粗蛋白日粮补充LYS、TRP和THR时氮保留效率最高，但只有当12%粗蛋白日粮同时补充缺乏的氨基酸和非必需氨基酸合成的氮源时，才能实现最大氮保留。
