Exploring the potential regulation mechanisms of host-microbiome comprehensive interactions on growth traits in Cyprinus carpio

The interaction between gut microbiota and host genetic factors in regulating host growth is receiving increasing attention. However, the mechanism underlying host variations and gut microbiota in regulating growth is still unclear in aquatic species. In this study, muscle and gut microbiota samples were collected from common carp. Host genetic markers and gut microbiota 16S rRNA sequencing data were analyzed to dissect the interactions between host and gut microbiota on growth trait, revealing differences in the overall gut microbiota between the high-growth and low-growth groups. Ten bacterial taxa showed significant differences between the two groups. A genome-wide association study indicated three loci associated with the growth trait, while genes harboring the three loci were found to be associated with Iamia and Thermoactinomyces. The three loci (Chr18:6901682; Chr23:10968715; Chr32:16293406) were located within the genes PARD3B, RCC2, and ITGA10. Mutations at the RCC2 locus may disrupt the cell regulatory cycle, leading to an increase in immune-related bacterial taxa, triggering an immune response in fish, and significantly impacting the growth rate of the common carp. Our study offers valuable insights into how host genome variations can influence growth traits by impacting gut microbiota, serving as a reference for understanding the intricate relationship between fish and gut microbiota. This research holds paramount significance for advancing engineered microbiome technology in aquaculture.