Institute of Dairy Science, MoE Key Laboratory of Molecular Animal Nutrition, College of Animal Sciences, Zhejiang University, Hangzhou 310058, PR China.
Institute of Dairy Science, MoE Key Laboratory of Molecular Animal Nutrition, College of Animal Sciences, Zhejiang University, Hangzhou 310058, PR China.
Food Res Int. 2021 Nov;149:110682. doi: 10.1016/j.foodres.2021.110682. Epub 2021 Sep 1.
Cow's milk is a highly-nutritious dairy product part of human diet worldwide. Rumen-protected methionine (RPM) is widely used to improve lactation performance of dairy cows, but understanding of the effects of RPM on milk nutrients composition are still limited. In this study, twenty mid-lactating dairy cows were supplemented with 20 gm/day RPM for 8 weeks to investigate the responses of milk nutritional composition to RPM. Metabolomics was applied for analyzing milk metabolites and 16S rRNA gene sequencing was used for analysis of rumen microbial composition. Milk fat content and yield were significantly increased after RPM supplementation. Totally 443 compounds belonging to 15 classes were identified, among which 15 metabolites were significantly changed. The functional nutrient α-ketoglutaric acid were significantly increased in the milk after RPM supplementation. We found 48 significantly differing bacterial genera in the rumen after supplementing RPM. Multi-omics integrated analysis revealed the higher abundance of Acetobacter, unclassified_f_Lachnospiraceae and Saccharofermentan contributed to the improved milk fat. In addition, the enriched abundance of Thermoactinomyces, Asteroleplasma, and Saccharofermentan showed positive correlations with higher α-ketoglutaric acid of milk. Our results uncover the metabolomic fingerprint and the key functional metabolites in the milk after supplementing RPM in dairy cows, as well as the key rumen bacteria associated with them. These findings provide novel insights into the development of functional dairy products that enriched the functional nutrient α-ketoglutaric acid or high milk fat.
牛奶是一种营养丰富的乳制品，是全世界人类饮食的一部分。包被蛋氨酸（RPM）被广泛用于提高奶牛的泌乳性能，但对 RPM 对牛奶营养成分的影响的理解仍然有限。在这项研究中，20 头泌乳中期的奶牛每天补充 20 克 RPM，持续 8 周，以研究 RPM 对牛奶营养成分的反应。代谢组学用于分析牛奶代谢物，16S rRNA 基因测序用于分析瘤胃微生物组成。RPM 补充后，牛奶脂肪含量和产量显著增加。总共鉴定出 443 种属于 15 类的化合物，其中 15 种代谢物发生了显著变化。在 RPM 补充后，功能性营养物质α-酮戊二酸在牛奶中的含量显著增加。我们发现补充 RPM 后瘤胃中有 48 个显著不同的细菌属。多组学综合分析显示，添加 RPM 后，阿克曼氏菌属、未分类的 f_毛螺菌科和糖发酵短杆菌的丰度增加，有助于提高牛奶脂肪。此外，Thermoactinomyces、Asteroleplasma 和 Saccharofermentan 的丰度增加与牛奶中α-酮戊二酸的增加呈正相关。我们的研究结果揭示了奶牛补充 RPM 后牛奶的代谢组学特征和关键功能代谢物，以及与这些代谢物相关的关键瘤胃细菌。这些发现为开发富含功能性营养物质α-酮戊二酸或高脂肪的功能性乳制品提供了新的思路。
