Characterising the Yellow Muscle Phenotype of Common Carp by Muscle Carotenoids, Fatty Acid Composition and Multi-Omics Analysis

Muscle color affects the market value of common carp (Cyprinus carpio), but the pigmentary and metabolic basis of the yellow muscle phenotype remains unclear. In this study, we compared muscle carotenoids, fatty acid profiles, and multi-omics data between wild yellow muscle (YC) and normal muscle (NC) common carp. YC showed significantly higher yellowness (b*) value, but there were no significant differences in the lightness (L*) and redness (a*) values. Total carotenoid was higher in YC and positively correlated with b*value. YC had higher saturated fatty acids (SFA) and n-3 polyunsaturated fatty acids (n-3 PUFA) proportions, including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), but lower n-6 and total PUFA, despite unchanged crude fat content. Total carotenoid content correlated with multiple fatty acids but not crude fat. Multi-omics analyses converged on glycerophospholipid metabolism, unsaturated fatty acid biosynthesis, and arachidonic acid metabolism, and cd36, scarb1, and bco2 were upregulated in YC muscle. In summary, these findings indicate that carotenoid accumulation underlies enhanced yellowness, while lipid remodeling and related transport processes may facilitate carotenoid retention in YC.