Enhancing Growth, Immunity and Disease Resistance in Nile Tilapia (Oreochromis niloticus) Through Dietary Sodium Butyrate Supplementation

Abstract

This study investigates the effects of dietary sodium butyrate supplementation (0.5% and 1%) on the growth performance, hematological and biochemical parameters, oxidative stress markers, and gene expression of Nile tilapia (Oreochromis niloticus) before and after exposure to Aeromonas hydrophila. Fish were fed sodium butyrate-supplemented diets for 56 days, after which they were challenged with A. hydrophila to evaluate immune responses and disease resistance. Growth parameters, including weight gain and feed conversion ratio, significantly improved in sodium butyrate-fed fish, with the 0.5% group exhibiting the highest growth performance. Hematological indices such as red blood cell count, hemoglobin, and packed cell volume increased in supplemented groups, indicating improved oxygen transport and immune readiness. Biochemical markers showed reduced ALT and AST levels, suggesting enhanced liver function, while higher total protein and globulin levels reflected improved immune competence. Sodium butyrate also enhanced antioxidant defense mechanisms; evidenced by increased superoxide dismutase, catalase, and glutathione peroxidase activities and decreased malondialdehyde levels. Gene expression analysis revealed an upregulation of TNF-α and IL-1β before infection, indicating a pre-activated immune system without excessive inflammation. At the same time, post-infection, sodium butyrate-fed fish exhibited higher NF-κB, TNF-α, and IL-1β expression, suggesting a stronger immune response. After infection, sodium butyrate-supplemented fish maintained better hematological and biochemical profiles, experienced lower oxidative stress, and exhibited enhanced immune responses compared to the control group. The findings suggest that dietary sodium butyrate, particularly at 0.5%, can significantly improve Nile tilapia's growth, immunity, and disease resistance, making it a promising functional feed additive for sustainable aquaculture.