Alteration of gut microbiota composition and function of Indian major carp, rohu (Labeo rohita) infected with Argulus siamensis

Gut microbiome homeostasis is critical in preventing diseases. However, the effect of disease on gut microbiota assembly remains unclear. At present, there are no reports on the composition and functional analysis of in-testinal microbiota of Indian major carp, rohu (L. rohita) infected with ectoparasite, Argulus. In this study, we analysed and compared the intestinal microbiota of healthy and Argulus-infected rohu by 16S rRNA amplicon sequencing. Argulus infection could significantly influence the diversity and richness of the gut microbiota. However, abundance of Actinobacteria and Patescibacteria were enriched significantly in Argulus-infected fish. Venn diagram revealed that there were many more unique genera in the infected group as compared to control fish. The genera, Stenotrophomonas and Pirellula were significantly increased in infected fish while the abundance of Reyranella was decreased. LEfSe analysis showed a significant enrichment in abundances of 11 taxa in healthy group and 17 taxa in infected group. Furthermore, genera Rubellimicrobium, Dielma, Hyphomicrobium, Reyranella, Streptomyces and Cloacibacterium performed the best in differentiating between both the groups. Predicted microbiota function by PICRUSt revealed that the gut microbiota of infected fish was mainly associated with enriched synthesis of chitinases, chitin binding proteins, osmoprotectant proteins and sulfatases enzymes. There was a positive association between the structural and functional composition of the gut microbiota. The results indicated that the Argulus infection could affect the intestinal microbiota composition and function of rohu.

Automated summary

The study found that Argulus infection significantly affects the diversity and richness of intestinal microbiota in rohu fish, with an enrichment of Actinobacteria and Patescibacteria. Infected fish showed a higher number of unique genera compared to healthy fish, with significant increases in certain genera like Stenotrophomonas and Pirellula, and a decrease in Reyranella. The composition and function of the gut microbiota were positively associated, and the predicted function in infected fish suggested an enrichment in the synthesis of chitinases, chitin binding proteins, osmoprotectant proteins, and sulfatases enzymes.