School of Animal Sciences, Louisiana State University Agricultural Center, Baton Rouge 70803, USA.
J Anim Sci. 2011 Aug;89(8):2415-24. doi: 10.2527/jas.2010-3756. Epub 2011 Mar 7.
Four experiments were conducted to determine the Lys requirement, the maximum amount of supplemental Lys that does not decrease growth performance, and to determine the order of limiting AA beyond Lys, Thr, Trp, and Met in a corn-soybean meal diet for 20- to 45-kg pigs. All experiments were conducted for 27 to 28 d with purebred or crossbred barrows and gilts, which were blocked by initial BW. Treatments were replicated with 4 to 6 pens of 4 to 6 pigs per pen. In all experiments, pigs and feeders were weighed on d 0, 14, and 27 or 28. At the beginning and end of all experiments, blood samples were obtained from all pigs to determine plasma urea N (PUN) concentrations. In Exp. 1, 0.830, 0.872, 0.913, and 0.955% standardized ileal digestible (SID) Lys was fed, whereas 0.747, 0.788, 0.830, 0.872, and 0.913% SID Lys was fed in Exp. 2. Broken-line analysis requirement estimates could not be estimated from any response variable in Exp. 1, but in Exp. 2, using ADG and PUN, the estimated SID Lys requirement was 0.83%. In Exp. 3, 0, 0.118, 0.191, 0.264, and 0.335% supplemental Lys was added to achieve 0.83% SID Lys in all diets, and Thr, Trp, and Met were supplemented to maintain Thr:Lys, Trp:Lys, and TSAA:Lys of 0.65, 0.18, and 0.60, respectively. Based on ADG, ADFI, and G:F, up to 0.23% supplemental Lys can be added along with supplemental Thr, Trp, and Met without negatively affecting growth performance; PUN was linearly decreased (P < 0.001) by supplemental Lys. In Exp. 4, treatments were 1) positive control (PC) without supplemental AA, 2) negative control (NC) with 0.335% supplemental Lys + 0.140% l-Thr + 0.035% l-Trp + 0.117% dl-Met, 3) NC + 0.044% l-Val, 4) NC + 0.021% l-Ile, and 5) NC + 0.044% l-Val + 0.021% l-Ile. Individual addition of Val and Ile did not improve (P > 0.10) ADG or G:F compared with the NC. The combined addition of Val + Ile resulted in ADG that was intermediate between the PC and NC diets but not different from either diet (P > 0.10); G:F was not improved (P > 0.10) to that observed in pigs fed the PC diet. The PUN was not different (P > 0.10) among pigs fed diets with supplemental AA but less (P < 0.10) than pigs fed the PC. The results of this research indicate that the Lys requirement for 20- to 45-kg pigs is 0.83% SID Lys, up to 0.23% supplemental Lys (0.29% l-Lys·HCl or 0.45% l-Lys·SO(4)) can be added along with supplemental Thr, Trp, and Met without negatively affecting growth performance, and another AA besides Val and Ile may be limiting growth performance in a corn-soybean meal diet with 0.335% supplemental Lys.
四个实验旨在确定赖氨酸（Lys）的需要量、最大添加量（不降低生长性能），以及确定在玉米-豆粕基础饲粮中，20-45kg 猪除 Lys、苏氨酸（Thr）、色氨酸（Trp）和蛋氨酸（Met）以外的其他 AA 的限制顺序。所有实验均采用纯种或杂交公猪和母猪进行，以初始体重为基础进行分组。处理在每个重复内采用 4-6 个栏，每个栏 4-6 头猪。在所有实验中，在第 0、14 和 27 或 28 天对猪和饲料进行称重。在所有实验的开始和结束时，从所有猪中采集血样，以确定血浆尿素氮（PUN）浓度。在实验 1 中，饲粮中添加 0.830、0.872、0.913 和 0.955% 可消化真可利用 Lys（SID Lys），而在实验 2 中添加 0.747、0.788、0.830、0.872 和 0.913% SID Lys。在实验 1 中，不能根据任何响应变量估计出线性需求估计值，但在实验 2 中，使用 ADG 和 PUN，估计的 SID Lys 需要量为 0.83%。在实验 3 中，在所有饲粮中添加 0、0.118、0.191、0.264 和 0.335% 的补充 Lys 以达到 0.83% SID Lys，同时补充 Thr、Trp 和 Met 以维持 Thr:Lys、Trp:Lys 和 TSAA:Lys 分别为 0.65、0.18 和 0.60。基于 ADG、ADFI 和 G:F，可添加高达 0.23% 的补充 Lys 以及补充 Thr、Trp 和 Met，而不会对生长性能产生负面影响；PUN 线性降低（P＜0.001）与补充 Lys 有关。在实验 4 中，处理为 1）阳性对照（PC），不添加 AA；2）阴性对照（NC），添加 0.335% 补充 Lys+0.140% l-Thr+0.035% l-Trp+0.117% dl-Met；3）NC+0.044% l-Val；4）NC+0.021% l-Ile；5）NC+0.044% l-Val+0.021% l-Ile。单独添加 Val 和 Ile 并没有改善 ADG 或 G:F（P＞0.10）与 NC 相比。Val 和 Ile 的联合添加导致 ADG 处于 PC 和 NC 饲粮之间，但与任何饲粮均无差异（P＞0.10）；G:F 没有得到改善（P＞0.10），与饲喂 PC 饲粮的猪相同。饲喂添加 AA 的饲粮的猪的 PUN 没有差异（P＞0.10），但低于饲喂 PC 的猪（P＜0.10）。本研究结果表明，20-45kg 猪的 Lys 需要量为 0.83% SID Lys，可添加高达 0.23% 的补充 Lys（0.29% l-Lys·HCl 或 0.45% l-Lys·SO4），同时添加补充 Thr、Trp 和 Met，不会对生长性能产生负面影响，除 Val 和 Ile 以外的另一种 AA 可能会限制含有 0.335% 补充 Lys 的玉米-豆粕饲粮的生长性能。
