Experiments were conducted with 270 Abore Acre male broilers to study the influence of dietary chlortetracycline(CTC) on the bursal, thymus and spleen weight index and T,B cell proliferation and antibody responses of broilers. Results show that 50mg/kg CTC had no significant inhibitory effect on thymus and spleen weight index, and T,B cell proliferation of broilers at 21 day old. 150mg/kg CTC had significant inhibitory effect on bursal , thymus and spleen, and T,B cell proliferation(P<0. 05). Dietary CTC ha...