Synergistic effects of dietary selenium nanoparticles and vitamin C improve growth performance, immune response, and antioxidant status of juvenile common carp (Cyprinus carpio)

Introduction: This study aimed to investigate the synergistic effects of dietary selenium nanoparticles (Se-NPs) and vitamin C (VC) on growth, body composition, antioxidant defense, immunity, and serum biochemical indexes of common carp (Cyprinus carp) juveniles. Methodology: The test diets were supplemented with three levels of Se-NPs (0, 0.5, and 1 mg/Kg) and three levels of VC (0, 500, and 1000 mg/Kg): the basal diet without supplemental Se-NPs and VC (VC(0)SeNPs(0); control), 0.5 mg Se-NPs /Kg (VC(0)SeNPs(0.5)), 1 mg Se-NPs /Kg (VC(0)SeNPs(1)), 500 mg VC/Kg (VC(500)SeNPs(0)), 1000 mg VC/Kg (VC(1000)SeNPs(0)), 500 mg VC/Kg and 0.5 mg Se-NPs (VC(500)SeNPs(0.5)), 1000 mg VC/Kg and 0.5 mg Se-NPs (VC(1000)SeNPs(0.5)), 500 mg VC/Kg and 1 mg Se-NPs (VC(500)SeNPs(1)), 1000 mg VC/Kg and 1 mg Se-NPs (VC(1000)SeNPs(1)). The fish were randomly divided into nine experimental groups in triplicate tanks per treatment and fed on their respective diets for 60 days. Results: The findings displayed that fish fed with VC(500)SeNPs(1) and VC(500)SeNPs(0.5) diets had significantly (P < 0.05) higher specific growth rates when compared to other groups. The lowest feed conversion ratio was detected in the VC(1000)SeNPs(1) group and the highest in the control group (P < 0.05). VC, Se-NPs, and their interaction had no significant effect on serum malondialdehyde, ACH50, and IgM (P > 0.05). However, the best parameters associated with antioxidant capacity (higher serum levels of superoxide dismutase and total reduced glutathione) and physiological status (higher concentration of serum globulin and lower amounts of aspartate aminotransferase and lactate dehydrogenase) belonged to the VC(1000)SeNPs(1) and VC(500)SeNPs(1) groups. The results suggest that the Se-NPs and VC combination more efficiently influence the common carp's growth performance, antioxidant status, immunity, and physiological parameters. Conclusion: Overall, the diet enriched with 500 mg VC and 1 mg Se-NPs /Kg (VC(500)SeNPs(1)) is suitable for boosting the growth and immunity of common carp.