Mastitis is one of the most prevalent diseases in dairy farming worldwide. The gut microbiota plays an important role in the regulation of systemic and local inflammatory diseases, such as mastitis. However, the regulatory mechanism of the gut microbiota on mastitis is still unclear. Thus, the aim of this study was to investigate the function and regulatory mechanisms of the gut microbiota in host defense against mastitis caused by Staphylococcus aureus (S. aureus) infection. Increased blood-milk barrier permeability, and S. aureus-induced mastitis severity were observed gut microbiota-dysbiosis mice compared with those in control mice. Moreover, feces microbiota transplantation (FMT) to microbbiota-dysbiosis mice reversed these effects. Furthermore, established disruption of commensal homeostasis results in significantly increased abundance of pathogenic Enterobacter bacteria, while the relative abundance of short-chain fatty acid (SCFAs)-producing bacterial phyla (Firmicutes and Bacteroidetes) was significantly reduced. However, FMT to gut microbiota-dysbiosis mice reversed these changes. In addition, dysbiosis reduced the levels of SCFAs, and administration of sodium propionate, sodium butyrate, and probiotics (butyrate-producing bacteria) reversed the changes in the blood-milk barrier and reduced the severity of mastitis induced by S. aureus. In conclusion, this new finding demonstrated that the gut microbiota acts as a protective factor in host defense against mastitis and that targeting the gut-mammary gland axis represents a promising therapeutic approach for mastitis treatment.

Endometritis is an inflammatory disease of the uterus caused by bacterial infection, and it affects both human and animal health.

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Background: Laminitis is a classic problem in the dairy industry, which can cause a great economic loss. However, the etiology and pathogenesis of laminitis have yet to be understood. In recent years, the microbiota has been the focus of much investigation in the search for various diseases. The present study aimed to explore the relationship between ruminal bacterial microbiota and laminitis. Results: The serum of healthy and laminitis bovines (n=8, respectively) collected from farms was used to detect concentrations of LPS, lactic acid, and histamine by the detection kits. This study used 16S rRNA sequencing to identify the differences in the bacterial community. The results showed that there was a significant increase in LPS and lactic acid in the laminitis group. Furthermore, microbial data analysis revealed that the laminitis group increased the abundance of bacteria with acid metabolites, such as Candidatus Saccharimonas, Saccharofermentans, Erysipelotrichaceae UCG-009, and Erysipelotrichaceae UCG-008, and [Clostridium] papyrosolvens and Ruminococcaceae bacterium AE2021.Conclusions: In summary, the changes in ruminal bacteria may potentially serve as the risk of laminitis.