Exploring the muscle-hardening mechanisms via the muscle-gut axis in tilapia (Oreochromis niloticus) fed with faba bean (Vicia faba L.) supplementary diets

This study investigated influences of faba bean (Vicia faba L.) supplementary diet (VFSD) on tilapia muscle texture through muscle-gut axis. Tilapia were fed diets with varying VSFD contents for 60 days. Results indicated no significantly growth changes across groups. However, VFSD increased muscle hardness and chewiness, with higher collagen deposition between muscle fibers. Transcriptome revealed an increase in differentially-expressed genes (DEGs) related to myofibril component and TGF-beta, MAPK, FOXO, insulin pathways. Crucial DEGs among interaction network between these pathways, including foxo3, mitf, smad1, smad7, and flt1, were validated via qPCR. Gut microbiota analysis showed VFSD decreased Pseudomonas, Ralstonia, and Aurantimicrobium abundance, while increased Rhodobacter, Akkermansia, and Propionibacteriaceae, which significantly impacting quorum sensing and ABC transporters. Microbiota variation highly correlated with muscle DEGs, suggesting a link between muscle phenotype and gut microbiota. In summary, VFSD alters meat texture by influencing collagen deposition and myofibril reconstruction, which may be regulated by LPS- and ROS-related pathways through altering the composition of the microbial community.