Linking diet to growth, nutrient composition, and flavor characteristics in Chinese mitten crab (Eriocheir sinensis): a study based on biochemical composition and intestinal microbiota

Background The search for sustainable alternatives to fish meal in aquafeeds is critical for the aquaculture industry. However, the impact of alternative protein sources on the comprehensive quality of Chinese mitten crab (Eriocheir sinensis) remains underexplored. Methods This study investigated the effects of dietary supplementation with beef liver (BL), housefly maggot (HM), or frozen trash fish (FTF) on the comprehensive quality of E. sinensis . Conclusion Our results highlight that BL and FTF, in particular, confer distinct and significant advantages. Results indicated that BL and HM significantly enhanced growth performance, while FTF had no adverse effects. BL supplementation notably increased muscle crude protein, essential amino acids, and key minerals (K, Fe, Cu). FTF supplementation led to the highest deposition of PUFAs, including EPA and DHA. Volatile compound analysis revealed that dietary regimens distinctively shaped the flavor profile. Partial least squares-discriminant analysis identified 15 key flavor markers, with 2-Butanone (M) (imparting fruity and cereal notes) being the most significant. Furthermore, BL and FTF modulated the gut microbiota and enhanced antioxidant capacity. Mechanistically, these quality improvements are primarily attributed to the modulation of nutrient deposition, lipid oxidation, and amino acid metabolism, likely mediated by shifts in the intestinal microbiota. These findings demonstrate that BL and FTF are effective dietary strategies for improving the muscle quality, flavor, and health of E. sinensis , offering promising and sustainable alternatives to conventional feeds.