Analysis of the differences in the microflora of milk from two dairy farms in Sichuan province based on high-throughput sequencing technology

Abstract:

[Objective] This experiment studied the microbial flora in healthy milk and mastitis milk from two dairy farms to explore the similarities and differences of milk flora in different dairy farms, and to assess whether their effects on milk metabolism are the same.[Methods] The 16S rRNA high-throughput sequencing technology was used to determine the 16S rRNA V4 region sequence of microorganisms in the milk of 6 healthy cows and 6 mastitis cows in two dairy farms. The structure and diversity of bacterial community were compared, and the differences in milk flora within and between the two farms were analyzed.[Results] A total of 4013234 Raw Reads were obtained from the four groups of milk samples, and 2887024 Clean Reads were obtained after filtering. No significant differences were found in Chao index, Ace index, Shannon index and Simpson index of Alpha diversity (P>0.05); Four groups of samples with Beta diversity are clustered respectively; In farm 1 and farm 2, the dominant bacteria causing cow mastitis were Klebsiella and Escherichia, respectively; the abundances of Escherichia and Staphylococcus in the healthy milk in farm 2 were significantly higher than those in farm 1; the abundance of Escherichia and Lactococcus in the mastitis milk in farm 2 were significantly higher than those in farm 1; the abundance of Psychrophilic bacteria in the healthy milk of the two dairy farms were 31.87% and 38.72% respectively; correlation analysis and functional prediction analysis showed that there was a significant difference in the relationship between the healthy milk and the dominant species of mastitis in the two dairy farms; significant differences in metabolic pathways were found in both Level 1 and Level 2 in farm 1, while no significant differences in metabolic pathways were found in farm 2.[Conclusion]] This experiment studied the similarities and differences of microflora between healthy milk and mastitis milk in two dairy farms, and provided a theoretical basis for the prevention of mastitis in the two dairy farms and the quality control of raw milk during cold chain transportation.