Dairy cows are at high risk of fatty liver disease in early lactation, but current preventative measures are not always effective. Cows with fatty liver have lower circulating branched-chain amino acid (BCAA) concentrations whereas cows with high circulating BCAA levels have low liver triglyceride (TG). Our objective was to determine the impact of BCAA and their corresponding ketoacids (branched-chain ketoacids, BCKA) on production performance and liver TG accumulation in Holstein cows in the first 3 weeks postpartum. Thirty-six multiparous Holstein cows were used in a randomized block design experiment. Cows were abomasally infused for the first 21 d postpartum with solutions of 1) saline (CON, n = 12); 2) BCA (67 g valine, 50 g leucine, and 34 g isoleucine, n = 12); and 3) BCK (77 g 2-ketovaline calcium salt, 57 g 2-ketoleucine calcium salt, and 39 g 2-ketoisoleucine calcium salt, n = 12). All cows received the same diet. Treatment effects were determined using PROC GLIMMIX in SAS. No differences were detected for body weight, body condition score, or dry matter intake averaged over the first 21 d postpartum. Cows receiving BCK had significantly lower liver TG concentrations compared to CON (6.60% vs. 4.77%, standard error of the mean (SEM) 0.49) during the first 3 weeks of lactation. Infusion of BCA increased milk yield (39.5 vs. 35.3 kg/d, SEM 1.8), milk fat yield (2.10 vs. 1.69 kg/d, SEM 0.08), and lactose yield (2.11 vs. 1.67 kg/d, SEM 0.07) compared with CON. Compared to CON, cows receiving BCA had lower plasma glucose (55.0 vs. 59.2 mg/dL, SEM 0.86) but higher β-hydroxybutyrate (9.17 vs. 6.00 mg/dL, SEM 0.80). Overall, BCAA supplementation in this study improved milk production, whereas BCKA supplementation reduced TG accumulation in the liver of fresh cows.

中文翻译：

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皱胃输注支链氨基酸或支链酮酸改变新鲜奶牛的泌乳性能和肝脏甘油三酯

奶牛在泌乳早期患脂肪肝的风险很高，但目前的预防措施并不总是有效。患有脂肪肝的奶牛循环支链氨基酸 (BCAA) 浓度较低，而循环 BCAA 水平较高的奶牛肝脏甘油三酯 (TG) 较低。我们的目的是确定 BCAA 及其相应的酮酸（支链酮酸，BCKA）对荷斯坦奶牛产后前 3 周的生产性能和肝脏 TG 积累的影响。三十六头经产荷斯坦奶牛被用于随机区组设计实验。产后前 21 天，对奶牛进行皱胃注射 1) 生理盐水 (CON, n = 12)；2) BCA (67 g 缬氨酸、50 g 亮氨酸和 34 g 异亮氨酸，n = 12)；3) BCK（77 g 2-酮缬氨酸钙盐、57 g 2-酮亮氨酸钙盐和 39 g 2-酮异亮氨酸钙盐，n = 12）。所有奶牛都接受相同的饮食。使用 SAS 中的 PROC GLIMMIX 确定治疗效果。产后 21 天内的平均体重、身体状况评分或干物质摄入量没有检测到差异。在泌乳期的前 3 周，与 CON 相比，接受 BCK 的奶牛肝脏 TG 浓度显着降低（6.60% vs. 4.77%，平均值标准误差 (SEM) 0.49）。输入 BCA 增加了产奶量（39.5 vs. 35.3 kg/d，SEM 1.8）、乳脂产量（2.10 vs. 1.69 kg/d，SEM 0.08）和乳糖产量（2.11 vs. 1.67 kg/d，SEM 0.07）与 CON 相比。与 CON 相比，接受 BCA 的奶牛血浆葡萄糖较低（55.0 vs. 59.2 mg/dL，SEM 0.86），但 β-羟基丁酸较高（9.17 vs. 6.00 mg/dL，SEM 0.80）。总体而言，本研究中补充 BCAA 提高了产奶量，而补充 BCKA 则减少了新鲜奶牛肝脏中 TG 的积累。