Nano-Selenium supplementation Improves Meat Quality, Protein Deposition, and Selenoprotein Gene Expression in Channel Catfish (Ictalurus Punctatus).

Selenium (Se) is a vital trace element for aquatic organisms. This study investigated the impact of dietary nano-selenium (Nano-Se) on growth, muscle nutritional quality, protein deposition, and selenoprotein gene expression in channel catfish (Ictalurus punctatus). A total of 12,000 catfish (85.74 ± 5.75 g) were randomly allocated into four groups (0, 1.5, 3.5, and 5.0 mg/kg Nano-Se) for 60 days. Optimal Nano-Se supplementation (3.5 mg/kg) significantly improved weight gain rate (WGR), specific growth rate (SGR), and feed conversion ratio (FCR) compared to the control. Additionally, Nano-Se enhanced muscle protein, lipid content, and free amino acid levels while modulating fatty acid composition, indicating improved flesh quality. Histological analysis revealed increased myofiber diameter, suggesting muscle growth promotion. Mechanistically, Nano-Se enhanced protein deposition by activating the PI3K/AKT/TOR pathway, stimulating protein synthesis, while simultaneously inhibiting proteolytic pathways (ubiquitin-proteasome and autophagy-lysosome systems). Furthermore, Nano-Se upregulated 17 key selenoprotein genes (Gpx1a, Gpx2, Gpx3, Gpx9, Selenoh, Selenoi, Selenok, Selenom, Selenop, Selenot1a, Selenot2, Selenow1, Selenow2, Selenoe, Selenoo1, Dio2, and Dio3b), implicating their roles in muscle development and oxidative stress regulation. The above results indicate that adding Nano-Se to feed can improve growth performance, flesh nutritional quality, muscle protein deposition, and selenoprotein genes expression of channel catfish.