Dietary Supplementation with Nano-Curcumin Improves the Meat Quality and Nutrition Value of Largemouth Bass (Micropterus salmoides) Fed with a High-Carbohydrate Diet

This study investigated the effects of curcumin nanoparticles on the flesh quality of largemouth bass on a high-carbohydrate diet. A total of 180 fish (11.01 ± 0.02 g) were fed three semi-purified diets: the Control group (LC) were supplemented with standard carbohydrate (10%), the experimental group (HC) were supplemented with 15% carbohydrate, and the experimental group were supplemented with 0.2% nano-curcumin added to 15% carbohydrate (HCN) for 6 weeks. Results showed that a* value, taurine, valine, isoleucine, histidine, cystine, fatty acids (C17:0 and C20:2n6), MDA (malondialdehyde) content, and SOD (Superoxide dismutase) activity were significantly elevated (p < 0.05) in HC. Muscle fibers showed significant increases in horizontal diameter, longitudinal diameter, and cross-sectional area (p < 0.05), as well as up-regulated expression levels of the MRFS (myogenic regulatory factor) family gene and MSTN (myostatin) (p < 0.05), and a significant decrease in C16:1n7 in HC (p < 0.05). Importantly, the HCN group enhanced the muscle quality of largemouth bass by elevating the L* value, valine, isoleucine, arginine and cystine, C20:2n6, decreasing (p < 0.05) refrigeration loss, chewability, firmness and hardness, then MDA content and SOD activity, and downregulating (p < 0.05) MSTN and MRFS family gene expression levels to improve largemouth bass muscle quality.