Vitamin E nanoemulsion enhances porcine sperm quality and reproductive performance via antioxidant enhancement and fatty acid metabolism regulation.

Vitamin E (VE) is widely used as an antioxidant in boar semen preservation. Its low water solubility and limited bioavailability, however, compromise its functional efficacy during storage. To address these limitations, we developed a lecithin-stabilized vitamin E nanoemulsion (NE) to enhance its dispersibility and antioxidant efficacy. Semen from Duroc boars was diluted in Beltsville thawing solution (BTS) containing either 0.6 mM NE, 4 mM free VE, or no additive, and stored at 17 °C. Compared to VE and control groups, NE significantly enhanced sperm motility, preserved the structural integrity of the plasma and acrosomal membranes, and maintained mitochondrial function, while reducing oxidative stress and DNA fragmentation over a 7d storage period (P < 0.01). Untargeted metabolomics revealed that NE supplementation regulated key pathways including unsaturated fatty acid metabolism and glutathione-related antioxidation. Artificial insemination (AI) trials involving 637 sows confirmed that NE-treated semen improved total and healthy piglet numbers per litter (P < 0.05), without adverse effects. These findings suggest that NE provides an effective and practical strategy for enhancing boar semen preservation and reproductive outcomes in porcine production.