Applications of Nano-Selenium in the Poultry Industry: An Overview.

Nanotechnology has emerged as a transformative tool in animal production, offering novel strategies to enhance productivity, health, and product quality. Among trace elements, selenium (Se) plays an essential role in antioxidant defence, immune regulation, and redox balance through its incorporation into selenoproteins. Selenium nanoparticles (SeNPs), synthesized via chemical, physical, or biological methods, have shown superior bioavailability, stability, and lower toxicity compared to traditional organic and inorganic selenium forms. This review explores the synthesis, physicochemical properties, and metabolic fate of SeNPs, emphasizing their advantages in poultry production systems. In poultry, SeNPs exhibit potent antioxidant and anti-stress effects by enhancing the activity of glutathione peroxidase, superoxide dismutase, and thioredoxin reductase, thereby mitigating lipid peroxidation and oxidative tissue damage. Their immunomodulatory effects are linked to improved lymphocyte proliferation, cytokine regulation, and increased immunoglobulin levels under normal and stress conditions. SeNP supplementation has been associated with enhanced growth performance, feed efficiency, carcass quality, and reproductive outcomes in broilers, layers, and quails. Furthermore, selenium nanoparticles have demonstrated therapeutic potential in preventing or alleviating chronic diseases such as cancer, diabetes, cardiovascular dysfunction, and neurodegenerative disorders. SeNPs also serve as biofortification agents, increasing selenium deposition in poultry meat and eggs, thus improving their nutritional value for human consumption. However, selenium's narrow safety margin requires careful dose optimization to avoid potential toxicity. This review highlights the multifaceted benefits of selenium nanoparticles in poultry nutrition and health, while underscoring the need for further studies on grey SeNPs, long-term safety, and regulatory frameworks. Integrating SeNPs into poultry production represents a promising strategy to bridge animal health, food security, and public nutrition.