Altered bacterial-fungal balance in the intestine of bullfrogs (Rana catesbeiana) with enteritis

The present study aimed to elucidate the relationship between gut microbiota composition and enteritis in bullfrogs, which is a species of significant economic value in aquaculture. By comparing the gut microbiota of healthy bullfrogs (HG), bullfrogs with enteritis (DG), and bullfrogs in the wild (WG), we sought to identify the microbial community changes associated with enteritis and understand the dynamics of bacterial and fungal interactions in different environments. Utilizing high-throughput sequencing of 16S rRNA gene and ITS amplicons, we analyzed the gut microbiota of the three groups. Our findings showed that the Shannon index of bacterial communities in diseased bullfrogs was lower than that in healthy ones. Dominant bacterial phyla such as Proteobacteria, Bacteroidetes, and Firmicutes had varying abundances among the groups. Opportunistic pathogens like Aeromonas and Vibrio were enriched in DG, while beneficial bacteria were more abundant in HG. The bacterial network complexity is the highest in the WG group, the fungal network complexity is the highest in the HG group, and the complexity of bacteria-fungus network interaction is the highest in the DG group. Our research demonstrates significant alterations in the gut microbiota composition and interactions in bullfrogs with enteritis. The findings highlight the importance of maintaining a balanced microbial community in the gut to prevent enteritis. This study provides foundational insights into the microbial ecology of bullfrog intestines and offers potential strategies for managing and preventing enteritis in bullfrog aquaculture. This study reveals the microbial shifts in bullfrog intestines associated with enteritis, showing a disrupted bacterial and fungal balance that exacerbates disease. By identifying the enriched pathogens and the reduced beneficial bacteria in diseased bullfrogs, our research underscores the critical role of gut microbiota in health and disease. These insights are essential for developing targeted interventions to restore the microbial balance and prevent enteritis in bullfrog aquaculture, thereby enhancing economic sustainability. • Gut microbiota in healthy, diseased, and wild bullfrogs differ in composition, structure, and diversity. • Wild bullfrogs show more complex and closer gut bacteria interspecies interactions. • Diseased bullfrogs exhibit the most complex species correlation network.