The individual and combined effect of DHA and high-fat diet on flesh quality, antioxidant capacity and myofiber characteristics of grass carp (Ctenopharyngodon idellus)

Abstract

The impact of a high-fat diet (HFD) on the meat quality of farmed fish is a subject of considerable interest among researchers. While docosahexaenoic acid (DHA) is recognized for enhancing growth performance and muscle mass in fish, its potential to mitigate the adverse effects of HFD on meat quality remains uncertain. This study examined the nutritional value, textural properties, and muscle characteristics of grass carp (Ctenopharyngodon idellus) fed varying levels of DHA (0.0%, 0.5%, and 1.0%) under either a regular fat diet (5.0% lipid) or an HFD (10.0% lipid) for a period of eight weeks. Results indicated that the addition of DHA to both the normal fat diet and HFD significantly improved the nutritional and sensory qualities of fish fillets, increasing crude protein, polyunsaturated fatty acid (PUFA), and collagen content while preserving optimal muscle hardness and pH levels. The HFD group exhibited diminished antioxidant capacity, reduced sarcomere length, and mitochondrial structural damage, all effectively ameliorated through DHA supplementation. Moreover, dietary DHA supplementation at both lipid levels upregulated the expression of genes associated with myogenesis and protein synthesis. A two-way ANOVA revealed significant interactions between dietary DHA and lipids, influencing muscle pH, fatty acid composition, myofiber characteristics, antioxidant capacity, and gene expression related to muscle growth and protein synthesis. In conclusion, DHA supplementation can effectively mitigate the deterioration of fish flesh quality induced by HFD.