1Wageningen Livestock Research,Wageningen,P.O. Box 338,6700 Wageningen,The Netherlands.
2Ajinomoto Eurolysine S.A.S.,153 rue de Courcelles,75817 Paris,Cedex 17,France.
Animal. 2019 May;13(5):941-949. doi: 10.1017/S175173111800263X. Epub 2018 Oct 18.
Lowering protein level in diets for piglets urge to have knowledge on the piglet's requirements for essential amino acids (AA) and their interactions. The present studies aimed to determine the interaction between the dietary level of valine (Val) and tryptophan (Trp) and the effect of AA imbalance at two levels of dietary Val on the growth performance of post-weaning piglets. In Experiment 1 (duration 4 weeks), the effects of supplementation of free l-Val (1.0 g/kg) and/or l-Trp (0.5 g/kg) in a low-CP diet (CP 17.7%), marginal in Trp and Val, was studied in a 2×2 factorial design and using an additional reference treatment (CP 19.5%). In Experiment 2 (duration 5 weeks), the influence of a stepwise increase in excess supply of isoleucine (Ile), histidine (His) and leucine (Leu), up to 10, 10% and 30% relative to their requirement values respectively, was evaluated at 60% or 70% standardized ileal digestible (SID) Val relative to SID lysine, using a 3×2 factorial design. In Experiment 1, over the whole experimental period, feed intake (FI) was affected by dietary Trp level (P<0.05) and feed conversion ratio (FCR) by both the level of Trp and Val in the diet (both P<0.05). Increasing Trp level increased FI and decreased FCR while increasing dietary Val level reduced FI and increased FCR. For BW gain (BWG), there was an interaction between dietary level of Trp and Val (P<0.05). Valine supplementation decreased BWG using a diet marginal in Trp, whereas it increased BWG when using a Trp sufficient diet. Piglets fed the low-CP diet with adequate levels of Val and Trp showed at least same performance compared to piglets fed the high CP reference diet. In Experiment 2, increasing dietary Val improved FI and BWG (P<0.001) and tended to improve FCR. Dietary AA excess for Ile, His and Leu reduced FI and BWG (P<0.05) and only affected FCR (P<0.01) in the 1st week of the study. Dietary level of Val and AA excess did not show interactive effects, except for FCR over the final 2 weeks of the study (P<0.05). In conclusion, an interaction exists between dietary supply of Val and Trp on the zootechnical performance of post-weaning piglets and dietary AA excess for Ile, Leu and His, reduces growth performance of piglets in low-protein diets, independent of the dietary level of Val.
降低仔猪日粮中的蛋白质水平需要了解仔猪对必需氨基酸（AA）的需求及其相互作用。本研究旨在确定缬氨酸（Val）和色氨酸（Trp）日粮水平之间的相互作用，以及日粮 Val 水平不平衡对断奶后仔猪生长性能的影响。在实验 1（持续 4 周）中，采用 2×2 因子设计，并使用额外的参考处理（CP 19.5%），研究了在低 CP 日粮（CP 17.7%，Trp 和 Val 边缘）中补充游离 l-Val（1.0 g/kg）和/或 l-Trp（0.5 g/kg）的效果。在实验 2（持续 5 周）中，在 60%或 70%标准化回肠可消化（SID）赖氨酸相对于 SID 赖氨酸的基础上，逐步增加异亮氨酸（Ile）、组氨酸（His）和亮氨酸（Leu）的过量供应，分别达到 10%、10%和 30%，评估了 3×2 因子设计的影响。在实验 1 中，整个实验期间，饲料摄入量（FI）受到日粮 Trp 水平的影响（P<0.05），饲料转化率（FCR）受到日粮 Trp 和 Val 水平的影响（均 P<0.05）。增加 Trp 水平增加了 FI，降低了 FCR，而增加日粮 Val 水平降低了 FI，增加了 FCR。对于 BW 增益（BWG），日粮 Trp 和 Val 水平之间存在交互作用（P<0.05）。用 Trp 不足的日粮补充 Val 会降低 BWG，而用 Trp 充足的日粮补充 Val 会增加 BWG。用含有足够 Val 和 Trp 的低 CP 日粮喂养的仔猪至少与用高 CP 参考日粮喂养的仔猪表现相同。在实验 2 中，增加日粮 Val 提高了 FI 和 BWG（P<0.001），并倾向于改善 FCR。Ile、His 和 Leu 的日粮 AA 过量减少了 FI 和 BWG（P<0.05），仅在研究的第 1 周影响 FCR（P<0.01）。在研究的最后 2 周，除了 FCR 外（P<0.05），Val 和 AA 过量的日粮水平没有表现出互作效应。总之，Val 和 Trp 日粮供应之间存在相互作用，影响断奶后仔猪的生产性能，Ile、Leu 和 His 的日粮 AA 过量会降低低蛋白日粮中仔猪的生长性能，而与日粮 Val 水平无关。
