this study aimed to evaluate the effects of dietary supplementation with cinnamon and silver nanoparticles (Cin/Ag-NPs) on growth performance, antioxidant status, immune response, inflammatory biomarkers, and cecal microbiota in broiler chickens. A total of 600 one-day-old male broiler chicks were randomly allocated to six treatments with five replicate pens per treatment (20 birds per pen, n = 5 pens/treatment). The experimental diets were: NC group, broilers fed a basal diet without cinnamon or silver nanoparticles; PC, Broiler chickens fed a basal diet and supplied with drinking water containing 7 ppm silver nanoparticles; Cin 1, Cin 2 groups: Broiler chickens fed a basal diet supplemented with 150 and 300 ppm cinnamon respectively; Cin/Ag-NPs -1, 2 groups: Broiler chickens fed a basal diet with 150 or 300 ppm dietary cinnamon in conjunction with 7 ppm silver nanoparticles. Dietary supplementation with cinnamon and silver nanoparticles positively affected growth performance, antioxidant status, immune response, inflammatory biomarkers, and cecal microbiota in broiler chickens. Average daily gain increased and feed conversion ratio improved progressively from NC to PC, Cin-1, Cin-2, and Cin/Ag-NPs groups. Antioxidant indices with the greatest effects observed in Cin/Ag-NPs–supplemented birds. Pro-inflammatory cytokines were reduced, whereas anti-inflammatory and serum immunoglobulins increased in a dose-dependent manner. Furthermore, cecal Lactobacilli SPP populations were elevated and E. coli counts decreased progressively from NC to Cin/Ag-NPs groups. In conclusion, dietary supplementation with Cin/Ag-NPs, particularly at 300 ppm cinnamon with 7 ppm Ag-NPs, effectively enhanced growth performance, antioxidant defense, immunity, and gut health in broiler chickens, suggesting its potential as an alternative to antibiotic growth promoters.
