Comparative effects of Capsicum annuum selenium nanoparticles and sodium selenite on growth, antioxidant activity, bioaccumulation, and DNA damage in quails.

Selenium nanoparticles (Se-NPs), a nanoscale form of selenium, and sodium selenite (SS), an inorganic selenium source, were included in the diet of quails to evaluate their effects on growth performance, selenium accumulation, antioxidant status, and DNA damage. A total of 420 quails (14-day-old) were distributed into 5 groups. Each group consisted of 84 birds, arranged into 3 replicates (28 quails per replicate). The first group served as the control and received a basal diet, while the second and third groups were supplemented with Se-NPs at 0.2 and 0.4 mg/kg, respectively. The fourth and fifth groups received SS at 0.2 and 0.4 mg/kg, respectively. The feeding trial was conducted for 65 days. The results demonstrated that quails supplemented with Se-NPs (0.4 mg/kg) exhibited the highest body weight gain and performance index, as well as the lowest feed conversion ratio. Selenium bioaccumulation increased significantly in all examined organs and was greatest in the liver. Analytical selenium recovery from tissue samples ranged from 90.0 to 95.0%, supporting the reliability of tissue selenium quantification. Antioxidant enzyme activities, including catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx), were significantly enhanced in all selenium-supplemented groups, with the highest activities observed in birds receiving Se-NPs (0.4 mg/kg). Comet assay analysis revealed significant differences in DNA damage parameters among the treatment groups, with the highest level of DNA strand breaks observed in quails supplemented with SS (0.4 mg/kg). Correlation analysis and heatmap visualization demonstrated a strong positive association between selenium bioaccumulation and antioxidant enzyme activities, whereas DNA damage parameters showed predominantly negative associations with selenium accumulation. The findings indicate that Se-NPs enhance growth performance, selenium retention, and antioxidant defense and are associated with lower DNA strand breaks than SS. Therefore, Se-NPs may serve as an effective and promising selenium source for poultry nutrition, exhibiting a favorable biological response compared with sodium selenite.