Dietary supplementation of saffron petal extract and biochar synergistically improves performance, gut morphology, antioxidant status, and reduces ammonia emission in Japanese quails (Coturnix coturnix japonica)

Biochar, owing to its highly porous structure and strong adsorption capacity, has the potential to enhance gut health and nutrient utilization. Saffron ( Crocus sativus L .) petal extract is rich in phenolic compounds and flavonoids and exhibits pronounced antioxidant and immunomodulatory properties. However, the potential synergistic effects of these two feed additives in poultry nutrition have not been fully elucidated. The present study evaluated the combined effects of dietary biochar and saffron petal extract on growth performance, intestinal morphology, antioxidant status, and lipid metabolism in Japanese quails (Coturnix coturnix japonica ). A total of 500 quails were randomly allocated to five dietary treatments, each with five replicates of 20 birds per replicate: a control diet, probiotic-supplemented diet, biochar-supplemented diet, saffron petal extract–supplemented diet, and a combined biochar plus saffron petal extract diet. Growth performance indices, serum biochemical parameters, intestinal histomorphology, antioxidant markers, and ammonia emissions were assessed. Combined supplementation with biochar and saffron petal extract significantly improved (P < 0.05) body weight gain, FCR and cecal villus height compared with the control and probiotic-fed groups. Moreover, this group showed higher glutathione (GSH) and superoxide dismutase (SOD) compared to other treatments (P < 0.05). Additionally, combined diet decreased ammonia emissions at 24 and 48 h, suggesting improved environmental sustainability. The serum lipid profile was also favorably modulated in all additive treatments compared to the control, as evidenced by increased HDL concentrations and reduced triglyceride, LDL and total cholesterol levels. Cecal Coliforms and Salmonella populations were decreased (P < 0.05) in all additive-supplemented groups without any significant changes in total bacterial counts. In conclusion, dietary supplementation with biochar and saffron petal extract exerted synergistic effects on intestinal morphology, antioxidant defense, and lipid metabolism, ultimately resulting in enhanced growth performance and physiological health in Japanese quails.