Artificial pigmentation and flesh quality in red porgy (Pagrus pagrus)

Red porgy (Pagrus pagrus) is a highly valued species of increasing interest for the Mediterranean aquaculture, characterized by a natural red-pink skin coloration, which acquires a gray color under culture conditions. This study was carried out in order to define new diets to modify the pigmentation variability of the red porgy skin. Six thousand red porgy juveniles (29.21 ± 6.39 g) were randomly distributed in three tanks with a volume of 55 m each and fed for 8 months with three extruded diets supplemented with graded levels of synthetic carotenoids (GFP0, GFP30, and GFP60). Color, carotenoid content, fatty acid composition of fish skin, chemical and fatty acid composition of fish flesh, and digestive enzymes and histological analysis of the intestine and liver of the fish were determined. The results showed that the supplementation of the synthetic carotenoids affected significantly the skin color indexes with the higher values of redness, yellowness, and chroma recorded in the fish fed with the GFP60 diet, while the other parameters investigated were unaffected except the intestinal protease activities of the GFP60 group, which had lower results. The present study showed encouraging results for developing a new research, but they are not satisfying to the application of this carotenoid supplement feed for this species in production farming.