(2-Carboxyethyl)dimethylsulfonium Bromide (Br-DMPT) improves muscle flesh quality and antioxidant status of on-growing grass carp (Ctenopharyngodon idella) fed non-fish meal diets

High-quality flesh plays crucial roles in affecting the acceptance and market value of the fish products. In previous study, (2-carboxyethyl)dimethylsulfonium Bromide (Br-DMPT) supplementation enhanced the growth and digestive capacity of fish fed non-fish meal diet, whereas its impacts on fish flesh quality remain unknown. Here, we examined whether dietary supplementation with Br-DMPT could improve muscle nutritive value, flesh flavor, healthy fatty, acids physical properties and antioxidant status in on-growing grass carp (Ctenopharyngodon idella), which fed a fish meal (FM) diet group and five non-fish meal (NFM) diets supplemented with graded Br-DMPT concentrations group (0, 130.0, 260.0, 390.0, 520.0 mg/kg Br-DMPT diet group), respectively. After 60 days feeding trial, we observed that NFM diets with supplementing appropriate Br-DMPT: (1) improved muscle nutritive value and flesh flavor by increasing protein and lipid contents, healthcare fatty acids (docosahexaenoic acid and eicosapentaenoic acid), umami and sweet related amino acids (Aspartic acid, Glutamic acid, Serine, Alanine and Glycine)；(2) accelerated muscle physical properties by increasing tenderness, water holding capacity and pH, and decreasing cathepsin (B and L) activities and lactate content; (3) increased muscle antioxidant status by increasing the activities and gene expression levels of antioxidant enzymes, which appears to be associated with nuclear factor-erythroid 2-related factor 2 (Nrf2) signalling pathway. Importantly, no noticeable difference was observed between 260.0 mg/kg Br-DMPT diet group and FM diet group with respect to the most of above these parameters. Overall, dietary Br-DMPT supplementation improved muscle nutritive values, flesh flavor, healthy fatty acids and enhanced physical properties, antioxidant status of fish. Furthermore, this study further demonstrated that it is feasible for achieving non-fish meal diet application in aquafeeds and also provided a practical data for the non-fish meal diet formulation for aquaculture industry.