Potential of Zinc-L-Selenomethionine to Improve the Health of Weaned Piglets and Its Antioxidant Stress Mechanism Through Modulation of PI3K/AKT and Nrf2/Keap1 Signaling Pathways

Zinc-L-selenomethionine (Zn-L-SeMet), a novel organic selenium (Se) source, shows great potential in alleviating oxidative stress. This study first evaluated the potential of Zn-L-SeMet to improve the health of weaned piglets and investigated underlying molecular mechanisms. In vivo, 240 weaned piglets were assigned to five dietary groups, namely, a control group (basal diet without Se) and four groups supplemented with Zn-L-SeMet (0.1, 0.2, 0.3, or 0.4 mg Se/kg in basal diet) for 42 days. In vitro, an oxidative stress model was established using hydrogen peroxide (H₂O₂) in porcine intestinal epithelial cells (IPEC-J2) to investigate the mechanisms of Zn-L-SeMet against oxidative damage. The results showed that Zn-L-SeMet improved growth performance, enhanced antioxidant and immune function, stimulated thyroid hormone secretion, and upregulated expression of selenoprotein genes. In vitro, Zn-L-SeMet reduced H₂O₂-induced apoptosis, promoted IPEC-J2 viability, and enhanced activities of antioxidant enzymes, while reducing lactate dehydrogenase release, malondialdehyde and reactive oxygen species levels. Furthermore, Zn-L-SeMet significantly increased the expression levels of Keap1, NQO1, HO-1, ARE, p-Nrf2, p-PI3K, and p-AKT, and protein ratio of p-Nrf2/Nrf2, PI3K/PI3K, and p-AKT/AKT compared to the H₂O₂ group (<i>p</i> < 0.05). In conclusion, Zn-L-SeMet improves health status with antioxidant potential in weaned piglets, and the mechanism is associated with activation of PI3K/AKT and Nrf2/Keap1 pathways.