Fluctuation of biochemical, immunological, and antioxidant biomarkers in the blood of beluga (Huso huso) under effect of dietary ZnO and chitosan-ZnO NPs.

The objective of the present study was to investigate the effects of dietary supplementation with zinc oxide (ZnO) and chitosan-zinc nanoparticles (chitosan-ZnO NPs) on biochemical, immunological, and antioxidant biomarkers in blood of juvenile belugas (Huso huso). The beluga juveniles with initial weight of 287 ± 46 g were fed with eight experimental diets containing 0 g kg-1 ZnO (the control diet); 10, 20, and 40 mg kg-1 ZnO; and 10, 20, and 40 mg kg-1 chitosan-ZnO NPs and 36 mg kg-1 chitosan. After 28 days of culture, the fish were fed with ZnO and chitosan-ZnO NP-supplemented diets showed a more significant increase in total antioxidant capacity (TAC), superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), glutathione peroxidase (GPX), and glutathione S-transferase (GST) activity (p < 0.05) compared to the control group. There were no significant differences (p > 0.05) in malondialdehyde (MDA) and glucose level in all treatment groups. The results showed that with increasing levels of ZnO and chitosan-ZnO NPs, alternative complement activity (ACH50), and total immunoglobulin, total protein, albumin, and lysozyme had a significant increase in fish fed with ZnO and chitosan-ZnO NP-supplemented diets compared to the control group (p < 0.05). ALP, ALT, and AST enzyme activities showed significant difference between control and treatment groups (p > 0.05), while the levels of LDH enzyme activity, urea, and creatinine decreased by increasing both ZnO and chitosan-ZnO NP levels. These results demonstrated that dietary chitosan-ZnO NPs could improve the health status, immune function, and antioxidant capacity of the cultured beluga juvenile.