Effects of dietary zinc oxide and selenium nanoparticles on growth performance, immune responses and enzyme activity in rohu, Labeo rohita (Hamilton)

Abstract

A 120-day feeding trial was conducted to assess the effects of dietary supplementation of zinc oxide (ZnO) and selenium (Se) nanoparticles (NPs) on growth, immunological and enzymatic profiles in rohu, Labeo rohita. Fishes were fed with basal diet incorporated with laboratory-synthesized nanoparticles, viz., zinc oxide nanoparticles—10 mg/kg and Se nanoparticles—0.3 mg/kg throughout the experimental period. At an interval of every 30 days, treated and control fishes were randomly collected and subjected to estimation of growth, non-specific immune parameters and serum enzyme assays. It was observed that there was significant (p < 0.05) increase in growth and non-specific immune parameters like respiratory burst, lysozyme and myeloperoxidase activities as compared to the control group (only basal diet). Serum enzymatic profiles such as lactate dehydrogenase and alkaline phosphatase activities down-regulated (p < 0.05) in treated group compared to control group, and superoxide dismutase and acetylcholine esterase activity up-regulated in treated group. The relative percentage survival (RPS) found to be significantly higher in treated groups (60.00 ± 8.82%) as compared to control group (45.00 ± 6.17%) while challenged with virulent bacterial strain Aeromonas hydrophila. These results indicated that dietary supplementation of zinc oxide (ZnO) and selenium (Se) nanoparticles stimulates immunity and enhances resistance to bacterial infection in L. rohita.