Preparturient Oral Selenitetriglycerides Supplementation Elevates Erythrocyte Glutathione Peroxidase Activity and Modulates Hepatic TNF-α, PPAR-α, and PPAR-δ mRNA in Postparturient Holstein–Friesian Cows

The transition period in dairy cows, spanning late pregnancy and early lactation, is associated with substantial metabolic and immunological challenges, leading to increased oxidative stress and inflammation. Selenium (Se), particularly in organic forms, supports antioxidant defenses, immune function, and metabolic regulation. This study investigated the effects of supplementing periparturient Holstein–Friesian cows with orally administered selenitetriglycerides (0.5 mg Se/kg body weight/day starting 12 days before the expected calving date and continuing until parturition) on antioxidant enzyme activity and on the hepatic expression of key inflammatory and metabolic genes. Serum selenium concentrations and erythrocyte glutathione peroxidase (GSH-Px) activity were assessed before and after parturition, and hepatic gene expression levels of tumor necrosis factor alpha (TNF-α), peroxisome proliferator-activated receptor alpha (PPAR-α) and delta (PPAR-δ) were assessed 24 h and 7 days postpartum. Supplemented cows showed significantly elevated serum Se levels and increased GSH-Px activity, reflecting improved antioxidant capacity. Moreover, hepatic expression of TNF-α and PPAR-δ was significantly reduced postpartum in the supplemented group, whereas PPAR-α expression remained stable. These findings indicate that selenitetriglycerides effectively enhance antioxidant defenses, moderate inflammation, and stabilize metabolic pathways during the periparturient phase, potentially reducing postpartum metabolic disorders and improving dairy-cow health.