Role of copper oxide nanoparticles (CuO-NPs) as feed additives to improve immune and biological functions in Oreochromis niloticus

Abstract

Antibiotics have recently been replaced by nanoparticles in many medical applications. The main aim of this study was to evaluate the Nile tilapia fish's ability to use inorganic and CuO-NPs efficiently by looking at growth performance, specific changes in serum biochemistry, pro-inflammatory gene expression, immune response, intestinal morphometric measurement, and resistance to A. hydrophila challenge. One hundred thirty-five monosex Nile tilapia fish, weighing an average of 19.1±0.2g, were employed in this experiment. The fish were divided into three groups. Groups 2 and 3 received diets containing 2 and 4 mg of CuO-NPs /kg, respectively, whereas the first group received the standard diet with 4 mg of inorganic copper per kilogram. It is the first time that CuO-NPs were employed to O. niloticus diet with partial substitution of copper conventional form, importantly our results showed that growth performance has improved. In comparison to the control group, the fish group fed a diet containing 2 or 4 mg CuO-NPs/kg showed better feed efficiency parameters, resistance against A. hydrophila challenge, intestinal morphometric measurement, and immune response parameters (phagocytosis, lysozyme, and bactericidal activities). The best values (p˂0.05) were obtained by low CuO-NPs (2mg/kg diet) supplementation. Additionally, compared to the control, a lower dosage of CuO-NPs supplementation significantly (p˂0.05) down-regulated the CYP1A and IL-1β genes and decreased the levels of serum cholesterol. In conclusion, it is the first time that CuO-NPs were employed to O. niloticus diet with partial substitution of copper conventional form, importantly our results showed that feeding O. niloticus with 2 mg of CuO-NPs/kg improves their growth, immune system, and general health. Analogously, CuO-NPs have demonstrated promising therapeutic outcomes, encouraging the consideration of substituting sustainable aquaculture for the usage of antibiotics or other medications in fish diets.