Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506-0210, USA.
J Anim Sci. 2010 Jan;88(1):137-46. doi: 10.2527/jas.2008-1204. Epub 2009 Sep 25.
Four experiments were conducted to determine the effects of standardized ileal digestible (SID) Lys:calorie (Lys:Mcal) ratio on growth performance of 10- to 20-kg pigs of 2 different genotypes. Experiment 1 (360 pigs, average BW = 10.2 kg; source 1) and Exp. 2 (351 pigs; average BW = 9.3 kg; source 2), were both organized as a combination of 2 simultaneous experiments with the first set of diets consisting of 5 treatments with increasing SID Lys and the second set of diets consisting of 5 treatments with increasing energy density (Exp. 1: 9.9, 10.7, 11.5, 12.2, and 13.0 g/kg of Lys and 2.95, 3.09, 3.24, 3.38, and 3.52 Mcal/kg of ME, respectively; Exp. 2: 11.1, 11.9, 12.6, 13.4, and 14.2 g/kg and 2.95, 3.10, 3.25, 3.40, and 3.55 Mcal of ME/kg, respectively). In Exp. 1, increasing dietary SID Lys increased (linear, P < 0.01) ADG and G:F, and increasing dietary ME increased (quadratic, P < 0.05) G:F. In Exp. 1 the optimal Lys:Mcal ratio was estimated to be at least 4.1 g of Lys/Mcal of ME based on G:F. In Exp. 2, increasing dietary SID Lys increased (linear, P < 0.01) ADG and G:F. Increasing dietary ME increased (linear, P < 0.01) G:F. Because of the linear responses in this experiment, optimal Lys:Mcal ratio was at least 4.0 g of Lys/Mcal of ME. In Exp. 3 (350 pigs; average BW = 9.4 kg; source 1) and Exp. 4 (350 pigs; average BW = 7.5 kg; source 2), Lys:Mcal ratios in Exp. 1 and 2 were compared by titrating Lys at 2 energy levels. Pigs were fed diets with 2.95 or 3.29 Mcal/kg of ME with SID Lys:Mcal ratios of 3.1 to 4.1 g/Mcal of ME (Exp. 3) and 3.5 to 4.5 g/Mcal of ME (Exp. 4). In Exp. 3, there was an ME x Lys:Mcal ratio interaction (P < 0.03) for ADG. The greatest ADG was a Lys:Mcal ratio of 3.60 for pigs fed low ME and a ratio of 3.35 for pigs fed high ME. Gain:feed ratio increased with increased (P < 0.01) ME concentration and as Lys:Mcal ratio increased (quadratic, P < 0.01); the best G:F was observed at 3.67 g of Lys/Mcal of ME. In Exp. 4, there was a tendency for ME x Lys:Mcal ratio interaction (P < 0.08) for G:F. The greatest G:F was achieved with a Lys: Mcal ratio of at least 4.50 for pigs fed low ME and a ratio of 4.29 for pigs fed high ME. Results (i.e., lack of ADG response to high energy density) suggest pigs reared in this environment were not in energy dependent growth phases. These pigs needed approximately 11 g/d of SID Lys (19 g of Lys/kg of gain) to optimize ADG and G:F. Based on these results, optimal Lys:Mcal ratio may differ depending on daily caloric intake of the pig.
四个实验旨在确定标准化回肠可消化赖氨酸（SID Lys）与热量（SID Lys：Mcal）比值对两个不同基因型的 10-20 公斤猪的生长性能的影响。实验 1（360 头猪，平均体重为 10.2 公斤；来源 1）和实验 2（351 头猪；平均体重为 9.3 公斤；来源 2）都是由两个同时进行的实验组成，第一个实验的饲料由 5 种不同 SID Lys 和能量密度（实验 1：9.9、10.7、11.5、12.2 和 13.0 g/kg 的 Lys 和 2.95、3.09、3.24、3.38 和 3.52 Mcal/kg 的 ME；实验 2：11.1、11.9、12.6、13.4 和 14.2 g/kg 和 2.95、3.10、3.25、3.40 和 3.55 Mcal/kg 的 ME）组成，第二个实验由 5 种不同 SID Lys 和能量密度（实验 1：2.95、3.09、3.24、3.38 和 3.52 Mcal/kg 的 ME；实验 2：2.95、3.10、3.25、3.40 和 3.55 Mcal/kg 的 ME）组成。在实验 1 中，日粮 SID Lys 的增加（线性，P < 0.01）提高了 ADG 和 G:F，而日粮 ME 的增加（二次，P < 0.05）提高了 G:F。在实验 1 中，基于 G:F，估计 Lys:Mcal 比值的最佳范围至少为 4.1 g Lys/Mcal 的 ME。在实验 2 中，日粮 SID Lys 的增加（线性，P < 0.01）提高了 ADG 和 G:F。日粮 ME 的增加（线性，P < 0.01）提高了 G:F。由于本实验中存在线性反应，因此 Lys:Mcal 比值的最佳范围至少为 4.0 g Lys/Mcal 的 ME。在实验 3（350 头猪；平均体重为 9.4 公斤；来源 1）和实验 4（350 头猪；平均体重为 7.5 公斤；来源 2）中，实验 1 和 2 的 Lys:Mcal 比值通过在两个能量水平上滴定 Lys 进行比较。猪饲喂 SID Lys:Mcal 比值为 3.1 至 4.1 g/Mcal 的 ME 的 2.95 或 3.29 Mcal/kg 的 ME 的日粮（实验 3）和 SID Lys:Mcal 比值为 3.5 至 4.5 g/Mcal 的 ME 的 2.95 或 3.29 Mcal/kg 的 ME（实验 4）。在实验 3 中，ADG 存在 ME x Lys:Mcal 比值的互作（P < 0.03）。低 ME 组猪的最佳 ADG 是 Lys:Mcal 比值为 3.60，高 ME 组猪的最佳比值为 3.35。增益：饲料比随着 ME 浓度的增加（P < 0.01）和 Lys:Mcal 比值的增加（二次，P < 0.01）而增加；最佳 G:F 出现在 3.67 g Lys/Mcal 的 ME 时。在实验 4 中，G:F 存在 ME x Lys:Mcal 比值的互作（P < 0.08）的趋势。低 ME 组猪的最佳 G:F 是 Lys:Mcal 比值至少为 4.50，高 ME 组猪的最佳比值为 4.29。结果（即，高能量密度对 ADG 没有反应）表明，在这种环境中饲养的猪没有处于能量依赖性生长阶段。这些猪每天需要大约 11 g 的 SID Lys（19 g 的 Lys/kg 的增重）来优化 ADG 和 G:F。基于这些结果，最佳 Lys:Mcal 比值可能因猪的日采食量而异。
