Pigmentation, carotenoids, lipid peroxides and lipid composition of red porgy (Pagrus pagrus) skin reared under open-cage conditions

Pigmentation capability of red porgy (Pagrus pagrus) skin reared under open sea-cage conditions and fed an astaxanthin-enriched diet was studied. Skin lipid peroxide levels and lipid composition were also evaluated to establish the antioxidant role of astaxanthin under these sunlight-exposure conditions. Fish placed either in an offshore sea cage system (SC) or in an inland tank facility (T) housed inside a ‘shade-house’ enclosure were fed a commercial diet supplemented with 22 mg kg-1 astaxanthin. No differences in growth or survival were found. Both groups displayed a red skin, but SC fish presented a darker pigmentation, which externally reflected the higher deposition of melanin, astaxanthin and tunaxanthin found in its skin. The lower level of lipid peroxides found in SC fish might be related with the higher level of astaxanthin mentioned above. Nevertheless, lipid and fatty acid profiles did not show significant differences between groups. Our results indicate that sustainable production of red porgy with a natural red hue is possible on the basis of proper adjustment of two factors illumination and dietary astaxanthin.