Diet-Induced Modulation of Gut Microbiota Affects Meat Quality in Grass Carp (Ctenopharyngodon idellus)

Understanding meat quality and gut microbiota hold great potential for promoting healthy and sustainable fish production, while also contributing to fisheries management and conservation. However, differences in meat quality and the diversity, structure, and function of gut microbiota among fish across different feeding regimes remain poorly understood. This study compared meat quality and gut microbiota between grass carp (gc) and crisped grass carp (cgc) to support sustainable aquaculture and provide more tasted fish meat. Cgc exhibited higher levels of free amino acids, fatty acids, and collagen, whereas gc had greater concentrations of hydrolyzed amino acids, nucleotides, and antioxidant indices. Fatty acid composition differed significantly between the two. Gut microbiota diversity was higher in cgc, with Proteobacteria, Fusobacteriota, and Firmicutes being dominant, while gc was dominated by Proteobacteria, Bacteroidota, and Firmicutes. The microbial community structures differed significantly. Functional predictions showed 1612 COG and 2032 KEGG pathways varied between groups. Significant correlations were found between microbial abundance and meat quality traits, including fatty acids, hydrolyzed amino acids, and collagen. These findings offered valuable insights for enhancing fish nutrition, optimizing feed formulations, and improving aquaculture practices.