Under current dietary regimens, milk production by lactating sows is insufficient to sustain the maximal growth of their piglets. As precursors of glutamate and glutamine as well as substrates and activators of protein synthesis, branched-chain amino acids (BCAAs) have great potential for enhancing milk production by sows. Thirty multiparous sows were assigned randomly into one of three groups: control (a corn- and soybean meal-based diet), the basal diet + 1.535% BCAAs; and the basal diet + 3.07% BCAAs. The ratio (g/g) among the supplemental L-isoleucine, L-leucine and L-valine was 1.00:2.56:1.23. Diets were made isonitrogenous by the addition of appropriate amounts of L-alanine. Lactating sows had free access to drinking water and their respective diets. The number of live-born piglets was standardized to 9 per sow at d 0 of lactation (the day of parturition). On d 3, 15 and 29 of lactation, body weights and milk consumption of piglets were measured, and blood samples were obtained from sows and piglets 2 h and 1 h after feeding and nursing, respectively. Feed intake did not differ among the three groups of sows. Concentrations of asparagine, glutamate, glutamine, citrulline, arginine, proline, BCAAs, and many other amino acids were greater (P < 0.05) in the plasma of BCAA-supplemented sows and their piglets than those in the control group. Compared with the control, dietary supplementation with 1.535% and 3.07% BCAAs increased (P < 0.05) concentrations of free and protein-bound BCAAs, glutamate plus glutamine, aspartate plus asparagine, and many other amino acids in milk; milk production by 14% and 21%, respectively; daily weight gains of piglets by 19% and 28%, respectively, while reducing preweaning mortality rates by 50% and 70%, respectively. Dietary supplementation with up to 3.07% BCAAs enhanced milk production by lactating sows, and the growth and survival of their piglets.

中文翻译：

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日粮中添加支链氨基酸可提高哺乳母猪的产奶量和哺乳仔猪的生长

在目前的饮食方案下，哺乳母猪的产奶量不足以维持仔猪的最大生长。作为谷氨酸和谷氨酰胺的前体以及蛋白质合成的底物和活化剂，支链氨基酸 (BCAA) 在提高母猪产奶量方面具有巨大潜力。30 头经产母猪被随机分配到以下三组中的一组：对照组（以玉米和豆粕为基础的日粮）、基础日粮 + 1.535% 支链氨基酸；和基础饮食 + 3.07% BCAAs。补充的L-异亮氨酸、L-亮氨酸和L-缬氨酸的比例(g/g)为1.00:2.56:1.23。通过添加适量的 L-丙氨酸使日粮等氮。哺乳母猪可以自由获得饮用水和它们各自的饮食。在泌乳第 0 天（分娩当天），活产仔猪的数量标准化为每头母猪 9 头。在泌乳第3、15和29天，测量仔猪的体重和产奶量，分别在喂食和哺乳后2小时和1小时采集母猪和仔猪的血样。三组母猪的采食量没有差异。补充 BCAA 的母猪及其仔猪血浆中天冬酰胺、谷氨酸、谷氨酰胺、瓜氨酸、精氨酸、脯氨酸、支链氨基酸和许多其他氨基酸的浓度高于对照组（P < 0.05）。与对照相比，添加 1.535% 和 3.07% BCAAs 的膳食补充剂增加了（P < 0.05）牛奶中游离和蛋白质结合的 BCAAs、谷氨酸加谷氨酰胺、天冬氨酸加天冬酰胺和许多其他氨基酸的浓度；产奶量分别增加 14% 和 21%；仔猪日增重分别为 19% 和 28%，同时断奶前死亡率分别降低 50% 和 70%。日粮中添加高达 3.07% 的 BCAA 可提高哺乳母猪的产奶量以及仔猪的生长和存活率。