文献类型： 外文期刊

作者： Wang, Xinling ¹ ; Zeng, Hanfang ¹ ; Xu, Jie ¹ ; Zhai, Yunfei ¹ ; Xia, Haibin ¹ ; Xi, Yumeng ² ; Han, Zhaoyu ¹ ;

作者机构： 1.Nanjing Agr Univ, Coll Anim Sci & Technol, Nanjing 210095, Peoples R China

2.Jiangsu Acad Agr Sci, Key Lab Crop & Anim Integrated Farming, Minist Agr, Nanjing 210014, Peoples R China

关键词： free amino acid; microbial diversity; milk protein concentration; ruminal microbiota

期刊名称：JOURNAL OF ANIMAL SCIENCE （ 影响因子：3.338； 五年影响因子：3.243 ）

ISSN： 0021-8812

年卷期： 2022 年 100 卷 11 期

页码：

收录情况： SCI

摘要： The rumen is a vital organ containing vast amounts of microbes that play a key role in the digestion of nutrients and affect the production performance of ruminants. However, few studies have focused on the characterization of the ruminal microbiota composition and function in cows with long-term difference milk protein concentrations, and the relationship between milk protein concentration and ruminal microbiota remains elusive. In this study, we collected the data of milk protein concentrations of 1,025 Holstein cows for 10 mo on a commercial farm. Based on the milk protein concentrations, 30 cows were selected and divided into three groups (n = 10 per group): low milk protein group (LMP, milk protein concentration < 3.1%), medium milk protein group (MMP, 3.1% <= milk protein concentration < 3.4%), and high milk protein group (HMP, milk protein concentration >= 3.4%). The ruminal microbiome, metabolome, VFA concentrations and proportions, and amino acid profiles of the three groups were analyzed. The data showed that free amino acid (FAA) levels were lower in the rumen and higher in the plasma of HMP cows (P < 0.05). In addition, lower NH3 concentrations were observed in the rumen, plasma, and milk of the HMP cows (P < 0.05). Protease activity and isobutyric acid molar proportion in the rumen were lower in the HMP group (P < 0.05). Microbiome analysis showed that HMP cows had lower microbial diversity (represented as Shannon and Simpson indices) than LMP cows. At the genus level, lower relative abundances of Prevotella_1 and Ruminococcaceae_UCG_005 were observed in the HMP group (P < 0.05). At the operational taxonomic unit (OTU) level, a lower relative abundance of OTU3 (Prevotella ruminicola) was observed in the HMP group (P < 0.05). We found that the relative abundances of ruminal Prevotella_1 and OTU3 (Prevotella ruminicola) were negatively correlated with milk protein concentration (P < 0.05). These findings suggested that the cows with long-term high milk protein concentrations had lower microbial diversity and weaker protein degradation ability in the rumen. Furthermore, our observations identified a correlation between the milk protein concentration and ruminal microbiota. 16S rDNA sequencing evidence supports that the cows with long-term high milk protein concentration show lower microbial diversity, relative abundances of specific ruminal microbiota, and protease activity in rumen. Lay Summary This study aimed to assess the ruminal microbiome, metabolome, volatile fatty acid concentrations, and amino acid profiles of Holstein cows with different milk protein concentrations. Previous studies have reported that ruminal microbiota can affect the lactation performance of dairy cows. However, little is known about the composition and function of ruminal microbiota in dairy cows differing in milk protein concentrations. In this study, we collected the milk protein concentrations data of 1,025 Holstein cows for 10 mo on a commercial farm. Three groups of cows (n = 10 per group) with low, medium, and high milk protein concentrations were selected. We found that cows with long-term high milk protein concentrations had lower microbial diversity, relative abundances of specific ruminal microbiota, protease activity, and amino acid concentration in the rumen compared to the cows with long-term low milk protein concentration. Meanwhile, cows with long-term high milk protein concentration showed higher amino acid concentrations in the plasma and lower ammonia levels in rumen, plasma and milk than cows with low milk protein concentration. Our findings revealed the correlation between milk protein concentration and specific ruminal microbiota, and proposed a possibility that ruminal microbiota affected milk protein concentration by altering host amino acid profile.