Li Lei, Li Jiaxiao, Liu Zhihui, Jin Zihan, Wang Mengyang, Wu Ying, Zhang Zhihong, Hou Xinfeng, Yao Junhu, Zhang Jun
College of Animal Science and Technology, Northwest A&F University, Yangling, 712100, China.
National Center of Technology Innovation for Dairy, Inner Mongolia Dairy Technology Research Institute Co. Ltd, Hohhot, 010100, China.
J Anim Sci Biotechnol. 2025 Jun 12;16(1):83. doi: 10.1186/s40104-025-01207-8.
During the transition period, cows are prone to negative energy balance, which can lead to a decline in production performance and health in severe cases. In recent years, it has been discovered that bile acids (BAs) can act not only as fat emulsifiers but also as signaling molecules to regulate body metabolism. Although BAs have been used to some extent in monogastric and aquatic animals, their role in ruminants, particularly in transition cows, remains unclear. Therefore, this study aimed to determine the effects of BAs on the production performance, milk and plasma fatty acid and BA composition, and fecal microbiota in transition dairy cows.
Forty-six healthy transition Holstein dairy cows with similar conditions were randomly divided into two groups and supplemented with 0 or 20 g/d of BAs from 21 d before the expected calving to 21 d after calving. The production performance was tracked until 60 d after calving. The results indicated that BA supplementation significantly improved postpartum milk fat content and yields as well as the yields of unsaturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids in milk. There was a significant increase in the concentration of triglyceride and the proportion of C ≤ 16 fatty acids in the plasma of cows supplemented with BAs, while the concentration of β-hydroxybutyrate and the proportion of C > 16 fatty acids in the plasma decreased significantly. BA supplementation significantly altered the composition of the fecal bacterial community and increased the relative abundance of bacteria beneficial for BA metabolism and transformation (Romboutsia, Clostridium sensu_stricto_6, and Clostridium sensu_stricto_1). Functional prediction analysis showed that the relative abundance of bile salt hydrolase, 7α-hydroxysteroid dehydrogenase, and BA inducible E as well as the pathways related to BA metabolism also significantly increased in cows supplemented BAs. In addition, BA supplementation significantly altered the composition of plasma and fecal BAs, particularly increasing circulating secondary BA concentration, which might induce the complete oxidation of fatty acids in the liver and further reduce the concentration of β-hydroxybutyrate.
These findings highlight the potential benefits of BA supplementation in improving milk yields and quality, as well as influencing metabolic pathways in transition dairy cows. Meanwhile, further studies are needed to elucidate the underlying mechanisms and explore the broader implications of these results by using more tissue samples.
在围产期，奶牛容易出现能量负平衡，严重时会导致生产性能下降和健康问题。近年来，人们发现胆汁酸（BAs）不仅可以作为脂肪乳化剂，还可以作为调节身体代谢的信号分子。尽管胆汁酸在单胃动物和水生动物中已得到一定程度的应用，但其在反刍动物，特别是围产期奶牛中的作用仍不清楚。因此，本研究旨在确定胆汁酸对围产期奶牛生产性能、牛奶和血浆脂肪酸及胆汁酸组成以及粪便微生物群的影响。
46头条件相似的健康围产期荷斯坦奶牛随机分为两组，从预计产犊前21天至产后21天分别补充0或20 g/d的胆汁酸。跟踪生产性能直至产后60天。结果表明，补充胆汁酸显著提高了产后牛奶脂肪含量和产量以及牛奶中不饱和脂肪酸、单不饱和脂肪酸和多不饱和脂肪酸的产量。补充胆汁酸的奶牛血浆中甘油三酯浓度显著增加，C≤16脂肪酸比例显著增加，而血浆中β-羟基丁酸浓度和C>16脂肪酸比例显著降低。补充胆汁酸显著改变了粪便细菌群落组成，并增加了有利于胆汁酸代谢和转化的细菌（罗姆布茨菌属、严格梭菌属6和严格梭菌属1）的相对丰度。功能预测分析表明，补充胆汁酸的奶牛中胆盐水解酶、7α-羟基类固醇脱氢酶和胆汁酸诱导型E的相对丰度以及与胆汁酸代谢相关的途径也显著增加。此外，补充胆汁酸显著改变了血浆和粪便胆汁酸的组成，特别是增加了循环中次级胆汁酸浓度，这可能诱导肝脏中脂肪酸的完全氧化，进而降低β-羟基丁酸的浓度。
这些发现突出了补充胆汁酸在提高牛奶产量和质量以及影响围产期奶牛代谢途径方面的潜在益处。同时，需要进一步研究以阐明潜在机制，并通过使用更多组织样本探索这些结果的更广泛意义。
