Effect of different levels of dietary copper nanoparticles and copper sulfate on growth performance, blood biochemical profiles, antioxidant status and immune response of red sea bream (Pagrus major)

•Effects of dietary nanocopper (Cu-NPs) or copper sulfate (CuSO4) on red sea bream were investigated.•Fish that were fed with 2 mg Cu-NPs kg− 1 displayed improved growth performance.•Fish that were fed with Cu-NPs diets, showed higher antioxidant defense system.•Fish that were fed with Cu-NPs diets, showed higher immune response.•Supplementation of Cu-NPs was much effective than CuSO4 on red sea bream performances.

A 60 days feeding trial was conducted to evaluate the effects of dietary copper nanoparticles (Cu-NPs) or copper sulfate (CuSO4) on growth performance, blood biochemical profiles, antioxidant status and immune response of red sea bream (Pagrus major) (initial body weight: 3.30 ± 0.02 g). Six diets were formulated containing CuSO4 or 2, 4, 6 or 8 mg supplemental Cu as NPs were supplied to the basal diet (control). The obtained results showed that, fish fed diets supplemented with Cu-NPs at levels of 2 and 4 mg kg− 1 had the highest values of final body weight, weight gain, specific growth rate, feed intake, protein gain and tolerance against low-salinity stress. Significantly higher feed efficiency ratio, protein efficiency ratio, protein retention, whole body Cu content, protease activity, lysozyme activity and total serum protein were found at levels of 2 mg Cu-NPs kg− 1 diet when compared with the control group. Whole body protein of fish fed diet Cu-free diet was significantly lower than those of fish fed other diets. Fish fed diets supplemented with Cu-NPs at different levels gave the lowest values of plasma glucose. Furthermore, fish fed diets supplemented with Cu-NPs at 2 and 4 mg kg− 1 diet were in better conditions whereas, fish fed control diet implied comparatively higher oxidative conditions. Therefore, the data of the present study recommend adding 2 mg Cu-NPs per kg diet to improve fish growth, immune response and antioxidant defense system.Statement of relevanceEfficiency of copper for red sea bream.