Effects of Dietary Red Grape Extract on the Quality Traits in Juvenile European Sea Bass ( Dicentrarchus labrax L.).

Intensive fish farming is responsible for the occurrence of various stressors that negatively affect the health of cultured animals. Polyphenols are plant-derived compounds with biological activities and positive influences on the performances and immunity of fish. The aim of the present study was to evaluate the effects of dietary inclusion of a polyphenol extract obtained from Nero di Troia red grape on the quality of farmed sea bass (Dicentrarchus labrax) fillets. Three diets were tested: control (n = 90) received a conventional feed, whereas the two experimental groups (n = 90 each) received the control feed supplemented with the red grape polyphenol extract (GPE) at the concentration of 100 (GPE 100) or 200 mg/kg (GPE 200). The two GPE diets lowered (p < 0.05) the red (a *) and yellow (b *) indexes, fillet hardness, and total lipid content. Chewiness, concentration of saturated fatty acids, and the Atherogenic Index were higher (p < 0.05) in the control group; GPE diets increased (p < 0.05) the polyunsaturated fatty acids content. Furthermore, the concentration of malondialdehyde was lower (p < 0.05) in fillets of the GPE groups, thus confirming the antioxidant effect of the red grape extract and its effectiveness in preventing lipid oxidation.