Probiotics ameliorate atopic dermatitis by modulating the dysbiosis of the gut microbiota in dogs.

BACKGROUND

Canine atopic dermatitis (cAD) is a chronic inflammatory disease that significantly reduces the quality of life in dogs. Dysbiosis of the gut microbiota affects skin diseases through the gut-skin axis. Therefore, microbiota-targeted therapy may potentially serve as a new management strategy for cAD. The present study aimed to investigate the association between gut microbiota and cAD and to evaluate the effect of probiotics on the clinical symptoms of cAD and gut microbiota in dogs.

RESULTS

Gut microbiota was analyzed at baseline and after 8 and 16 weeks. Baseline analysis revealed significantly lower (p < 0.05) gut microbial diversity in dogs with cAD than in healthy dogs. Differential abundance analysis showed that Fusobacterium, Megamonas, Collinsella, unclassified Clostridiales, Bacillus, Helicobacter, and Caproiciproducens were significantly more abundant in healthy dogs. In contrast, Clostridioides, Erysipelatoclostridium, Clostridium, Terrisporobacter, and unclassified Ruminococcaceae were significantly more abundant in dogs with cAD, In addition, differential abundance analysis showed that the abundance of 46 metabolic pathways were significantly different between healthy dogs and dogs with cAD indicating the dysbiosis of the gut microbiota in cAD. Moreover, the clinical severity of cAD was negatively correlated (p < 0.05) with alpha diversity and the abundance of Fusobacterium and Megamonas. Notably, daily probiotic administration for 16 weeks significantly decreased the clinical severity (p < 0.05). Dogs with good prognoses exhibited significantly increased alpha diversity, whereas those with poor prognoses did not, suggesting that the therapeutic effects of probiotics may be mediated by changes in gut microbial diversity.

CONCLUSIONS

This study highlights the association between gut microbiota dysbiosis and cAD in dogs and demonstrates that probiotic administration can effectively ameliorate cAD by improving gut microbial dysbiosis. These findings provide a basis for novel microbiota-based therapies in cAD treatment.