Unlocking the Benefits of Organic Selenium: How Different Levels Affect Laying Hen Health and Egg Quality

This study evaluated the effects of organic selenium supplementation at different concentrations on laying hen performance, egg quality, and antioxidant status. We hypothesized that increasing levels of organic selenium would improve egg quality, antioxidant capacity, and Se deposition, outperforming inorganic selenium. This study provides novel insights by using a unique yeast strain (PTCC5052) and evaluating nonlinear Se dose–response patterns. A total of 360 Super Nick hens (38 weeks old) were randomly assigned to six groups and fed either a control diet (no selenium), a diet with 0.3 mg/kg Se from an inorganic source, or 0.1, 0.2, 0.3, or 0.4 mg/kg Se from an organic source derived from Saccharomyces cerevisiae PTCC5052—a unique yeast strain. Over 10 weeks, egg production, feed conversion ratio, egg quality, and Se deposition in eggs were assessed. Production performance was not significantly affected by selenium supplementation. However, hens receiving 0.3 and 0.4 mg/kg of organic Se showed significantly thicker eggshells and higher egg selenium content (p < 0.05). Antioxidant enzyme activities (glutathione peroxidase, superoxide dismutase) were significantly enhanced in organic Se groups, while malondialdehyde levels were reduced (p < 0.05). The strongest antioxidant capacity was observed at 0.1–0.2 mg/kg Se, suggesting a nonlinear dose–response pattern. Serum protein, uric acid, AST, and ALT remained unchanged. These results demonstrate that organic selenium from S. cerevisiae PTCC5052 improves egg quality and antioxidant capacity without affecting production performance, highlighting the importance of selenium source and dose–response dynamics.