Effects of dietary selenium nanoparticles on hematological and biochemical indices, immune and antioxidant system of Nile tilapia (Oreochromis niloticus)

This study was conducted to evaluate the effect of different concentrations of selenium nanoparticles on the hematological, serum biochemical indices, and antioxidant system of Nile tilapia (Oreochromis niloticus). Fish with an average weight of 31.1±1.0 g were distributed in 12 fiberglass tanks and were fed for 56 days with different concentrations of selenium nanoparticles including 0, T1 (0.5), T2 (1) and T3 (2 mg/kg of selenium nanoparticles). The highest number of red blood cells, hemoglobin and hematocrit were observed in T2 and T3, which statistically showed a significant difference with other treatments, especially the control treatment (P<0.05). The results showed a significant difference in the total protein and globulin levels of fish fed with a diet containing 1 and 2 mg/kg of selenium nanoparticles. In this study, the addition of 2 mg/kg of nano selenium to the diet lead to a significant decrease in glucose, cholesterol, and triglyceride levels, and the lowest values of these parameters were observed in the group fed with 2 mg/kg of nano selenium, which is significantly different from others. The activity level of liver enzymes including ALT and AST was the highest level in the control treatment and those lowest were observed in the 2 mg/kg nano selenium treatment (P<0.05). There was a significant difference in the amounts of catalase and superoxide dismutase enzymes among fish fed with 1 and 2 mg/kg of selenium nanoparticles compare to the treatment of 0.5 mg/kg of selenium nanoparticles (P<0.05). In conclusion, the effect of different concentrations of selenium nanoparticles, especially in the concentration of 2 mg/kg, had positive effects on the hematological, biochemical indices, and antioxidant system of Nile tilapia and this nanoparticle can be a suitable agent for improving available food quality in aquaculture.