Exercise recovers the decrease in nutritional value, sensory qualities, and antioxidant capacity in muscle induced by a high-fat diet in channel catfish (Ictalurus punctatus)

High-fat diets have been widely used in aquaculture because of their protein-sparing effect. However, high-fat diets have some negative effects on flesh quality in farmed fishes. This study investigated the potential of exercise to ameliorate the negative effects of a high-fat diet on the flesh quality of channel catfish ( Ictalurus punctatus ). A total of 120 channel catfish (54.58 ± 0.32 g) were randomly allocated to four treatments with triplicate tanks (10 fish per tank). Channel catfish were fed either a control diet (crude lipid = 6 %) or high-fat (HF) diet (crude lipid = 11 %) under two conditions: voluntary swimming (water velocity = 0.84 cm/s, 0 BL/s) and exercise (water velocity = 20.84 cm/s, 1 BL/s) for 58 days. We found that long-term intake of a HF diet adversely altered muscle composition and texture regardless of exercise, while impairing nutritional value and antioxidant capacity of voluntarily swum fish. However, the adverse effects observed with the HF diet on protein synthesis signaling ( s6k1 ), essential amino acids, and total amino acids were attenuated with exercise. The HF diet promoted fasn expression and inhibited lipid catabolism ( lpl and cpt1b ) in the voluntarily swum fish only. Exercise reduced lipid accumulation in the muscle by inhibiting lipid synthesis-related gene expression ( acaca and srebp1 ). Notably, exercise also inhibited fasn expression under the HF diet. These modulations were related to the activation of the AMPK/SIRT1/PGC-1α pathway. Moreover, exercise increased the levels of ARA, EPA, DHA, and n-3 PUFAs in muscle under the HF diet, thereby enhancing its nutritional value. Additionally, exercise increased muscle collagen content and improved muscle cellularity by upregulating the expression of genes related to myofiber development ( myod1 and myhc ). Under the HF diet, exercise also suppressed the expression of mstna and mstnb . These modulations ultimately enhanced flesh hardness and improved overall texture. Furthermore, exercise increased taste-active free amino acids and decreased off-flavors in fillets regardless of diet, while increasing aromatic flavor substances under the HF diet, thereby improving sensory qualities. Exercise also elevated muscle catalase levels and improved muscle antioxidant capacity under the HF diet. Our study suggests that exercise effectively alleviates the adverse effects induced by a HF diet on the flesh quality of channel catfish.