Akkermansia muciniphila isolated from forest musk deer ameliorates diarrhea in mice via modification of gut microbiota.

BACKGROUND

The forest musk deer, a rare fauna species found in China, is famous for its musk secretion which is used in selected Traditional Chinese medicines. However, over-hunting has led to musk deer becoming an endangered species, and their survival is also greatly challenged by various high incidence and high mortality respiratory and intestinal diseases such as septic pneumonia and enteritis. Accumulating evidence has demonstrated that Akkermannia muciniphila (AKK) is a promising probiotic, and we wondered whether AKK could be used as a food additive in animal breeding programmes to help prevent intestinal diseases.

METHODS

We isolated one AKK strain from musk deer feces (AKK-D) using an improved enrichment medium combined with real-time PCR. After confirmation by 16S rRNA gene sequencing, a series of in vitro tests was conducted to evaluate the probiotic effects of AKK-D by assessing its reproductive capability, simulated gastrointestinal fluid tolerance, acid and bile salt resistance, self-aggregation ability, hydrophobicity, antibiotic sensitivity, hemolysis, harmful metabolite production, biofilm formation ability, and bacterial adhesion to gastrointestinal mucosa.

RESULTS

The AKK-D strain has a probiotic function similar to that of the standard strain in humans (AKK-H). An in vivo study found that AKK-D significantly ameliorated symptoms in the enterotoxigenic Escherichia coli (ETEC)-induced murine diarrhea model. AKK-D improved organ damage, inhibited inflammatory responses, and improved intestinal barrier permeability. Additionally, AKK-D promoted the reconstitution and maintenance of the homeostasis of gut microflora, as indicated by the fact that AKK-D-treated mice showed a decrease in Bacteroidetes and an increase in the proportion of other beneficial bacteria like Muribaculaceae, Muribaculum, and unclassified f_Lachnospiaceae compared with the diarrhea model mice.

CONCLUSION

Taken together, our data show that this novel AKK-D strain might be a potential probiotic for use in musk deer breeding, although further extensive systematic research is still needed.