EFFECTS OF DIETARY INCLUSION OF FISH OIL ETHYL ESTERS ON FATTY ACID PROFILE, PLASMA METABOLITES, AND LIVER OXIDATIVE STRESS IN EUROPEAN SEABASS (Dicentrarchus labrax)

The nutritional quality of dietary lipids plays a critical role in regulating physiological functions in marine fish, particularly through modulating tissue fatty acid composition, metabolic function, and cellular oxidative balance. In aquaculture, the selection of lipid sources not only influences growth performance outcomes but also affects key health-related biomarkers. While fish oil (FO) remains the standard for providing essential n-3 LC-PUFA such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), alternative lipid forms, including ethyl esters (EE) oil, have emerged as potential substitutes. EE oil differs from FO and vegetable oils (VO) in molecular structure and absorption kinetics, which may alter its biological efficacy. As marine fish species, including European seabass (Dicentrarchus labrax), rely on dietary sources of preformed n-3 LC-PUFA, understanding how novel lipid sources like EE oil impact lipid metabolism and redox status is essential for optimizing feed formulations. This study explores the effects of partial or total FO replacement with EE oil on growth, fatty acid profile, plasma metabolites, and hepatic oxidative stress, offering insights into the physiological integration of non-triglyceride lipid sources.