Gómez R S, Lewis A J, Miller P S, Chen H Y
Department of Animal Science, University of Nebraska, Lincoln 68583-0908, USA.
J Anim Sci. 2002 Mar;80(3):644-53. doi: 10.2527/2002.803644x.
Two experiments, each with 36 barrows with high-lean-gain potential, were conducted to evaluate apparent nutrient digestibilities and performance and plasma metabolites of pigs fed corn-soybean meal diets (CONTROL) and low-protein diets. The low-protein diets were supplemented with crystalline lysine, threonine, tryptophan, and methionine either on an ideal protein basis (IDEAL) or in a pattern similar to that of the control diet (AACON). Amino acids were added on a true ileally digestible basis. The initial and final BW were, respectively, 31.5 and 82.3 kg in Exp. 1 and 32.7 and 57.1 kg in Exp. 2. In Exp. 1, the CONTROL and IDEAL diets were offered on an ad libitum basis or by feeding 90 or 80% of ad libitum intake. Pigs were fed for 55 d. In Exp. 2, the CONTROL, IDEAL, and AACON diets were offered on an ad libitum basis or by feeding 80% of the ad libitum intake. Pigs were fed for 27 d. Pigs fed the CONTROL diet had greater (P < 0.05) ADG and feed efficiency (G/F) than pigs fed the IDEAL (Exp. 1 and 2) and AACON diets (Exp. 2). As the level of feed intake decreased, ADG decreased (P < 0.05), but G/F tended to improve (P < 0.10) for pigs fed 90% of ad libitum in Exp. 1 and for pigs fed 80% of ad libitum in Exp. 2. In Exp. 1, the apparent total tract digestibilities of DM and energy were greater (P < 0.01) for pigs fed the IDEAL diet than for pigs fed the CONTROL diet. In Exp. 2, the apparent total tract digestibility of protein was greatest in pigs fed the CONTROL diet (P < 0.05) and was greater (P < 0.05) in pigs fed the AACON diet than in pigs fed the IDEAL diet. Plasma urea concentrations were lower in pigs fed the IDEAL diet than in pigs fed the CONTROL diet, regardless of feeding level. For pigs fed the CONTROL diet, plasma urea concentrations were lower when feed intake was 80% of ad libitum (diet level, P < 0.01). In summary, pigs fed the IDEAL and the AACON diets gained less and had lower plasma urea concentrations than pigs fed the CONTROL diet. Based on these data, it seems that the growth potential of pigs fed the IDEAL and AACON diets may have been limited by a deficiency of lysine, threonine, and(or) tryptophan and that the amino acid pattern(s) used was not ideal for these pigs.
进行了两项试验，每项试验选用36头具有高瘦肉生长潜力的公猪，以评估饲喂玉米 - 豆粕型日粮（对照）和低蛋白日粮的猪的表观养分消化率、生产性能及血浆代谢物情况。低蛋白日粮按理想蛋白模式（IDEAL）或与对照日粮相似的模式（AACON）补充结晶赖氨酸、苏氨酸、色氨酸和蛋氨酸。氨基酸以真回肠可消化率为基础添加。试验1中猪的初始体重和末重分别为31.5 kg和82.3 kg，试验2中分别为32.7 kg和57.1 kg。在试验1中，对照和IDEAL日粮按自由采食或按自由采食量的90%或80%进行饲喂。猪饲喂55天。在试验2中，对照、IDEAL和AACON日粮按自由采食或按自由采食量的80%进行饲喂。猪饲喂27天。饲喂对照日粮的猪比饲喂IDEAL日粮（试验1和2）和AACON日粮（试验2）的猪具有更高（P < 0.05）的平均日增重（ADG）和饲料效率（G/F）。随着采食量水平降低，试验1中按自由采食量90%饲喂的猪和试验2中按自由采食量80%饲喂的猪的ADG降低（P < 0.05），但G/F有改善趋势（P < 0.10）。在试验1中，饲喂IDEAL日粮的猪的干物质和能量的表观全肠道消化率高于饲喂对照日粮的猪（P < 0.01）。在试验2中，饲喂对照日粮的猪的蛋白质表观全肠道消化率最高（P < 0.05），饲喂AACON日粮的猪的蛋白质表观全肠道消化率高于饲喂IDEAL日粮的猪（P < 0.05）。无论饲喂水平如何，饲喂IDEAL日粮的猪的血浆尿素浓度低于饲喂对照日粮的猪。对于饲喂对照日粮的猪，当采食量为自由采食量的80%时，血浆尿素浓度降低（日粮水平，P < 0.01）。总之，饲喂IDEAL和AACON日粮的猪比饲喂对照日粮的猪增重少且血浆尿素浓度低。基于这些数据，似乎饲喂IDEAL和AACON日粮的猪的生长潜力可能受到赖氨酸、苏氨酸和（或）色氨酸缺乏的限制，并且所采用的氨基酸模式对这些猪并不理想。
