Dietary protein source and taurine supplementation in European seabass: physiological responses to acute handling stress

The replacement of marine ingredients with processed animal proteins (PAP) in aquafeeds offers an alternative to conventional marine protein sources, but may also alter the supply of specific nutrients, including taurine. As taurine is involved in several physiological processes and its endogenous synthesis is limited in marine teleosts, changes in dietary taurine supply may influence the response to acute stress. This study aimed to investigate how replacing most marine ingredients with poultry meal and poultry blood meal, and supplementing the resulting diet with taurine, affected the physiological response and recovery of juvenile European seabass (Dicentrarchus labrax) following an acute handling challenge. Fish were fed for 15 days a marine ingredient-rich diet (MARINE), a PAP-based diet (PAP), or the PAP diet supplemented with 1% taurine (TAU). Following dietary conditioning, fish were subjected to netting and 1 min of air exposure. Samples were collected before the challenge (0 h) and at 1, 4 and 24 h afterwards to characterise the temporal dynamics of the response. The dataset includes growth performance and hepatosomatic index, plasma cortisol, glucose, lactate, cholesterol, triglycerides and lysozyme activity, as well as hepatic and intestinal redox parameters (superoxide dismutase, catalase, total glutathione and lipid peroxidation) and intestinal peroxidase activity. These data enable the integrated assessment of endocrine, metabolic, immune and tissue redox responses to acute stress and their temporal changes during recovery. They provide a basis for investigating how dietary protein source and taurine supplementation influence the physiological response of European seabass to a routine husbandry stressor.