Impact of selenium supplementation on antioxidant enzyme activity and liver gene expression in juvenile pangasius catfish (Pangasius pangasius)

This study examined the effect of dietary selenium (Se) fortification on growth efficiency, antioxidant status, and liver gene expression in juvenile pangasius catfish. Sodium selenite was incorporated into a basal diet at incremental levels of 0-2.0 mg Se/kg. This resulted in final Se concentrations of 0.63, 0.85, 1.15, 1.68, 2.10, and 2.65 mg Se/kg, respectively. A total of 15 fish, with an average individual weight of 5.6 +/- 0.1 g, were subjected to one of six dietary treatments and fed in triplicate over a 60-day period. A significant dose-related enhancement in growth performance was observed, with the optimal dietary Se requirement estimated at 1.75 mg Se/kg. Se-fortified diet significantly increased the activities of digestive enzymes (lipase and protease) as well as antioxidant enzymes, including catalase, glutathione peroxidase, and superoxide dismutase in the liver. Notably, the group fed 1.68 mg Se/kg displayed the highest levels of these enzymes. Additionally, selenium supplementation resulted in an upregulation of the relative expression of insulin-like growth factor 1X1 and 1X2 in the liver, highlighting its pivotal role in growth regulation. Blood parameters showed significant improvements in mean corpuscular hemoglobin and hemoglobin levels with Se supplementation. Proximate analysis showed increasing Se intake resulted in a significant rise in muscle protein content. In pangasius catfish, our results indicate that dietary selenium supplementation can enhance growth efficiency, antioxidant capacity, and hepatic gene expression.