Effects of Matricaria chamomilla -Derived Selenium Nanoparticles on Growth, Antioxidant, Immunity, and Gut Microbiota in Japanese Quails

Selenium nanoparticles (SeNPs) have emerged as a promising alternative to conventional selenium sources because of their superior bioavailability, lower toxicity, and enhanced biological activity. This study aimed to synthesize and characterize green-synthesized SeNPs using Matricaria chamomilla extract and evaluate their effects on growth performance, serum biochemistry, antioxidant status, immunity, and caecal microbiota in Japanese quails ( Coturnix coturnix japonica ). A total of 400 ten-day-old quails were randomly allocated to four dietary treatments with 10 replicates of 10 birds each for 35 days. The treatments included a control diet containing 0.2 mg/kg selenium as sodium selenite and diets supplemented with 0.2, 0.4, or 0.6 mg/kg green-synthesized SeNPs. Nanoparticles were characterized using dynamic light scattering, zeta potential analysis, transmission and scanning electron microscopy. Growth performance was recorded weekly, while serum biochemical indices, antioxidant enzymes, immunoglobulins, selenium concentration, and caecal microbiota were determined at the end of the trial. Dietary SeNP supplementation significantly increased body weight, body weight gain, and feed efficiency (P < 0.05) without affecting weekly feed intake. Total protein, globulin, antioxidant enzymes (SOD, GSH, and GPx), immunoglobulins (IgA, IgG, and IgM), and serum selenium concentration increased significantly (P < 0.001), whereas total cholesterol, triglycerides, LDL, VLDL, malondialdehyde, serum urea, total bacterial count, and Escherichia coli populations decreased (P < 0.001). In contrast, HDL concentration and lactic acid bacteria counts increased significantly (P < 0.001). Overall, dietary supplementation with green-synthesized SeNPs, particularly at 0.4–0.6 mg/kg, improved growth performance, antioxidant capacity, immune status, lipid metabolism, and intestinal microbial balance, demonstrating that biologically synthesized SeNPs represent an effective and sustainable selenium source for Japanese quail production.