Influence of Dietary Replacement of Fish Meal with Crayfish Shell Meal on the Skin Coloration, Muscle Texture, and Amino Acid Composition of Oujiang Color Common Carp Cyprinus carpio var. color

Abstract An 8‐week feeding trial was conducted to investigate the influence of dietary replacement of fish meal with crayfish shell meal (red swamp crayfish Procambarus clarkii ) on the skin coloration, muscle texture, and amino acid composition of Oujiang color common carp Cyprinus carpio var. color . One‐hundred‐eighty fish with average initial weight of 3.0 ± 0.5 g were fed with two isonitrogenous and isolipidic diets (a control diet and a crayfish shell meal diet with 25% substitution of fish meal protein [CSM25]). At the termination of the feeding trial, there were no significant differences between the two groups in terms of lightness ( L *), redness ( a *), and yellowness ( b *) values. Interestingly, one unexpected finding was the extent to which the highest value for total color difference (Δ E ) was observed in caudal skin. The springiness, adhesiveness, cohesiveness, gumminess, and chewiness of the muscle were not affected by the CSM25 diet in this study. Muscle hardness was decreased by dietary supplementation with crayfish shell meal, although this decrease was not significant. Notably, there were significant increases in the levels of threonine, leucine, and lysine in the CSM25 group. The current results indicate that crayfish shell meal can alter some essential amino acid levels in muscle. These findings might help others to better understand the influence of dietary replacement of fish meal with crayfish shell meal on skin coloration, muscle texture, and amino acid composition.