Effects of dietary nanocurcumin on growth, immunity and stress response in European seabass (Dicentrarchus labrax).

This experiment was conducted to evaluate the effects of dietary nanocurcumin on growth performance, feed utilization, innate immunity, antioxidant capacity, biochemical indices, and air exposure stress resistance in European seabass (Dicentrarchus labrax) fingerlings. Five isonitrogenous (47% crude protein) and isocaloric (21 MJ/kg dry matter) diets were formulated, supplemented with nanocurcumin at the following levels: 0, 100, 300, 600, and 900 mg/kg. The diets were administered to D. labrax (6.45 ± 0.08 g) for 65 days. Following the feeding trial, the fish were subjected to air exposure stress for 3 min followed by 2 h of recovery before sampling. The results indicated that dietary nanocurcumin significantly enhanced growth performance and feed utilization. Antioxidant status was improved, as evidenced by increased levels of reduced glutathione and catalase, along with decreased concentrations of malondialdehyde and hydrogen peroxide. In addition, nanocurcumin supplementation reduced the activities of hepatic enzymes, including aspartate aminotransferase and alanine aminotransferase, as well as stress indicators such as glucose, cortisol, and lactate dehydrogenase, both before and after air exposure stress. Immune responses were also enhanced, with higher levels of immunoglobulin M, immunoglobulin G, and complement components 3 and 4 observed in fish fed nanocurcumin-supplemented diets. Overall, dietary nanocurcumin improved growth performance, antioxidant capacity, and innate immunity, while mitigating stress responses in D. labrax, with optimum results obtained at a dietary inclusion level of 900 mg/kg.