Abstract
Background
The nutritional value and microbial diversity of fresh milk are shaped by the cows' environment and biological processes, leading to varied microbial profiles that can influence milk quality, fermentation, spoilage, and health outcomes. Analysing the microbial composition of milk can provide insights into its nutritional value and potential effects on human health. To this end, we investigated microbial composition on fresh milk, gathered from seven large-scale dairy farms in the southern and northern regions of Xinjiang, using metagenomic sequencing technology.
Results
Our findings indicated that the main phyla were Firmicutes, Proteobacteria, and Actinobacteria, with abundances of 7.57–7.76%, 5.60–5.78%, and 2.26–2.29%, respectively. At the genus level, the genera with the highest relative abundances were Sporosarcina, Streptococcus, and Escherichia, with relative abundances of 2.51–2.58%, 2.23–2.27%, and 1.93–1.97% respectively. When exploring species richness, it was observed that the XN group had the most operational taxonomic units, while the DR group had the fewest. Additionally, there were significant differences in the community structure between the ND group and the other six groups. Further, alpha diversity analysis revealed no significant variation in Chao1 indices across the seven sample groups, highlighting a significant difference in the Shannon index for ND samples and no significant differences in Shannon indices between the CJ, JY, KT, DR, and TR samples. The top three relative abundances in the microbial metagenome KEGG functional library were biological systems, human diseases, and environmental information processing; additionally, within the carbohydrate-active enzyme database, the three most abundant categories were glycosyltransferases, glycoside hydrolases, and carbohydrate-binding modules.
Conclusions
By identifying the significant differences in the microbial prevalence between milk obtained from different regions, this study demonstrated the microbial spectrum characteristics of fresh milk from Southern and Northern Xinjiang, offering a theoretical foundation for enhancing the quality of fresh milk in the area.