Department of Animal Science, Cornell University, Ithaca, NY 14853.
Department of Animal Science, Cornell University, Ithaca, NY 14853; China Agricultural University, Beijing, China 830052.
J Dairy Sci. 2021 Sep;104(9):9948-9955. doi: 10.3168/jds.2021-20169. Epub 2021 Jun 25.
In rodents and humans, the gut bacteria-derived metabolite trimethylamine N-oxide (TMAO) has been implicated in the progression of cardiovascular disease, chronic kidney disease, fatty liver, and insulin resistance; however, the effects of TMAO on dairy cattle health and milk production have not been defined. We aimed to determine whether intravenous TMAO infusion modifies measures of liver health, glucose tolerance, and milk production in early-lactation cows. Eight early-lactation Holstein cows (30.4 ± 6.41 d in milk; 2.88 ± 0.83 lactations) were enrolled in a study with a replicated 4 × 4 Latin square design. Cows were intravenously infused TMAO at 0 (control), 20, 40, or 60 g/d for 6 d. Washout periods lasted 9 d. Intravenous glucose tolerance tests (GTT) occurred on d 5. Blood was collected daily. Milk was collected on d -1, 0, 5, and 6. Urine was collected on d -1 and 6. Circulating metabolites, milk components, and TMAO concentrations in milk, urine, and plasma were quantified. Data were analyzed using a mixed model that included the fixed effects of treatment. Concentrations of TMAO in plasma, milk, and urine increased linearly with increasing dose. Dry matter intake and milk production were not modified by treatment. Daily plasma triacylglycerol, fatty acid (FA), and glucose concentrations were not modified. Serum albumin, total protein, globulin, total bilirubin, direct bilirubin, aspartate aminotransferase, γ-glutamyl transferase, and glutamate dehydrogenase concentrations were also not modified by treatment. Serum GTT glucose, FA, and insulin concentrations were not modified by treatment. Plasma total, reduced, and oxidized glutathione concentrations were also not modified by treatment. We conclude that a 6-d intravenous infusion of TMAO does not influence measures of liver health, glucose tolerance, or milk production in early-lactation dairy cows.
在啮齿动物和人类中，肠道细菌衍生的代谢产物三甲胺 N-氧化物（TMAO）已被牵连到心血管疾病、慢性肾病、脂肪肝和胰岛素抵抗的进展中；然而，TMAO 对奶牛健康和产奶量的影响尚未确定。我们旨在确定静脉内 TMAO 输注是否会改变泌乳早期奶牛的肝脏健康、葡萄糖耐量和产奶量的衡量标准。
将 8 头泌乳早期荷斯坦奶牛（泌乳 30.4 ± 6.41 d；2.88 ± 0.83 个泌乳期）纳入一项研究，该研究采用重复 4×4 拉丁方设计。奶牛每天静脉内输注 TMAO 0（对照）、20、40 或 60 g/d，持续 6 天。洗脱期持续 9 天。第 5 天进行静脉内葡萄糖耐量试验（GTT）。每天采集血液。在第-1、0、5 和 6 天采集牛奶。在第-1 和 6 天采集尿液。定量检测循环代谢物、牛奶成分以及牛奶、尿液和血浆中的 TMAO 浓度。使用包括处理固定效应的混合模型分析数据。
血浆、牛奶和尿液中 TMAO 的浓度随剂量的增加呈线性增加。处理未改变干物质摄入量和产奶量。每日血浆三酰甘油、脂肪酸（FA）和葡萄糖浓度不受处理影响。血清白蛋白、总蛋白、球蛋白、总胆红素、直接胆红素、天冬氨酸氨基转移酶、γ-谷氨酰转移酶和谷氨酸脱氢酶浓度也不受处理影响。血清 GTT 葡萄糖、FA 和胰岛素浓度不受处理影响。血浆总、还原和氧化型谷胱甘肽浓度也不受处理影响。
我们得出结论，6 天静脉内输注 TMAO 不会影响泌乳早期奶牛的肝脏健康、葡萄糖耐量或产奶量的衡量标准。
