Marine and freshwater crab meals in diets for red porgy (Pagrus pagrus): Effect on fillet fatty acid profile and flesh quality parameters

The present study was conducted to evaluate the effect of using river crab (Procamburus clarkii) meal (RC) and marine crab (Chaceon affinis) meal (MC) on the red porgy (Pagrus pagrus) fillet fatty acid profile and quality. Red porgy were fed during 193days with five diets: a control diet based on high-quality fish meal (CD); and four diets replacing 10% and 20% fish meal protein by protein from both RC and MC meals (RC10, RC20 and MC10, MC20). Fillet fat content resulted significantly higher in MC20 fish than the rest of diets. Feeding with both RC and MC meals slightly increased muscle contents of polyunsaturated (PUFA), arachidonic (ARA), eicosapentaenoic (EPA), and docosahexaenoic (DHA) fatty acids and n−3/n−6 ratio as well as decreased n−9 fatty acids, although difference is only significant for the ARA content. After inclusion of both crab meals, values of atherogenicity index (AI) resulted similar among treatments while thrombogenecity index (TI) was reduced, but not significantly, reflecting the higher n−3 fatty acid content in fillets from crab diets. Sensory analysis showed that red porgy fillets of all treatments were very well appreciated with some differences detected in only MC20 fillets, which had significantly higher scores in the attributes of oily odour and flavour, cohesiveness aspect and firmness texture compared to the rest of diets. RC meal dietary inclusion did not promote any changes in sensory evaluation panel. Instrumental muscle texture did not revealed differences between treatments. Results from TBARS of raw fillets showed that the inclusion of both crab meals clearly delays lipid oxidation compared to a FM based diet, during refrigerated storage at 4°C. Thus, for 4 and 7days of storage, fillets of RC or MC diets, attained significantly lower TBARS values than those fed on CD.