Résumé
Fish tissues, particularly rich in n-3 PUFA, are prone tolipid peroxidation that can damage cellular membranes,cause severe lesions and subsequently incidences of diseaseand mortality. However, fish possess antioxidant defences,such as vitamin E (VE) and antioxidant enzymes, to pro-tect them against oxidative damage. This study investigatedthe effects of an increasing gradient of oxidized dietarylipid on the survival, growth performance, skeletogenesisand antioxidant defensive processes occurring in Senegalesesole (Solea senegalensis) larvae. Four groups of fish werefed live prey enriched with experimental emulsions contain-ing an increasing gradient of oxidized oil: non-oxidized,NO+VE, 34.5 nmol MDA g1w.w.; mildly oxidized,MO+VE, 43.1 nmol MDA g1w.w.; highly oxidized, HO+VE, 63.3 nmol MDA g1w.w. and highly oxidized withoutVE, HO-VE, 78.8 nmol MDA g1w.w. The oxidation lev-els increased in enriched rotifers following the oxidationgradient of the emulsions, but were not affected in enrichedArtemiametanauplii. The oxidation status of Senegalesesole larvae increased during development, but this was notrelated to the dietary treatments. The increasing dietaryoxidation levels did not affect the fatty acid profile, sur-vival, growth performance and metamorphosis processes ofsole larvae. Senegalese sole seem to activate antioxidantdefence mechanisms in response to the increasing amountsof dietary peroxidized lipids, in a manner efficiently enoughto prevent detection of any alterations of these physiologi-cal processes. Antioxidant systems and detoxification mech-anisms appeared to occur through the consumption ofdietarya-tocopherol, the activation of the antioxidantenzymes (catalase, superoxide dismutase, glutathioneS-transferase, glutathione reductase) and the retention ofoxidized fat in the intestinal enterocytes for detoxificationprior to their utilization. However, fish fed the highestoxidized diet presented a reduction in bone mineralization,but lower incidence of deformities in the vertebral andcaudal regions than fish fed the other diets. This studyexemplifies the importance of rearing Senegalese sole larvaeon non-oxidized diets during the early larval developmentto avoid detrimental consequences in older fish, mostnotably in the process of skeletogenesis.KEY WORD