Toxicological Responses of Juvenile Gilthead Seabream to Enniatin B and Fumonisin B1

The replacement of ingredients from animal sources with plant-based ingredients is increasing the risk of contamination by mycotoxins in aquafeeds, potentially causing detrimental effects on fish welfare. However, limited research has been carried out so far on the impact of mycotoxins on fish health. Hence, the aim of this study was to assess the toxicological effects of the dietary emerging (enniatin B, ENNB) and regulated (fumonisin B1, FB1) mycotoxins (150 µg/kg) in different tissues of juvenile gilthead seabream (<i>Sparus aurata</i>) after 28 days of dietary exposure. Fitness indexes, plasma metabolites, and biomarkers of oxidative stress, metabolism, cellular, and neurotoxic damage were assessed. The exposure to each mycotoxin was sufficient to cause distinct effects in fish tissues. ENNB appears to be the most harmful mycotoxin to <i>S. aurata</i>, inducing changes on alkaline phosphatase and lipase activities in plasma, as well as protein and lipid degradation in liver. Increased lipid degradation was also induced in the brain by FB1 alone or combined with ENNB, whereas the exposure to the mixture inhibited acetylcholinesterase activity. Overall, this study contributes by highlighting the toxicological attributes of ENNB, thus reinforcing the need to include this mycotoxin in future legislation.