The results suggested that supplementation with 0.1% or 0.2% ZnCP modulated microbial populations and improved immune function and antioxidant status in the gastrointentinal (GI) tract, which may exert protective effects on the integrity of the mucosal barrier function of broilers, was as efficacious as 40 mg chlortetrecycline per kg in enhancing growth performance. the results indicated that ZnCP may be used as a new growth promoter instead of antibiotics in poultry feed.