According to 2 X 4 factorial design, 120 broilers were treated with CTC therapeutic dosage (500 mg/kg) and the same numbers of broilers were used as control.

• 试验采用2×4二因子试验设计方案，即对一半试鸡进行三天（15-17日龄）金霉素治疗剂量（500mg/kg）前处理，另一半试鸡不进行处理；