Fish guts - the key to preventing disease?

It has long been known that the gut microbiota of fish can greatly affect their susceptibility to certain pathogens. Many aquaculture farms are now opting to use probiotics and prebiotics to boost the gut microbiota of farmed fish to prevent disease rather than using antibiotics which can lead to antibiotic resistance arising within aquaculture systems.

Tran et al. conducted a study in 2018 with the aim of assessing whether there was a difference in the gut microbiota of grass carp (Ctenopharyngodon idellus) infected with an intestinal disease and that of healthy grass carp. These changes in gut microbiota were assessed through NGS-based 16S – rRNA sequencing.

It was found that there was a significant difference in the structures of microbial communities within the guts of healthy and diseased carp with members of the following genera being greatly increased in diseased fish: Dechloromonas, Methylocaldum, Planctomyces, Rhodobacter, Caulobacter, Flavobacterium, and Pseudomonas.

This study manged to shed light on the microbes associated with enteritis in carp which is a common disease found in fish in aquaculture operations that can frequently lead to death so this study has wide ranging implications for the early detection and prevention of this disease in aquaculture. However, quite a small group of fish were sampled, only 16, and the sampling was skewed towards diseased fish so by having more comprehensive and even sampling it may make the results more reliable and the results from the two groups more comparable.

Tran, N. T., Zhang, J., Xiong, F., Wang, G.-T., Li, W.-X., & Wu, S.-G. (2018). Altered gut microbiota associated with intestinal disease in grass carp (Ctenopharyngodon idellus). World Journal of Microbiology and Biotechnology, 34(6)