The control birds were fed the basal diet alone,the second treatment were fed basal diet added 50 mg/kg chlortetracycline(CTC),the other treatments fed the basal diet supplemented with 50,100,150 mg/kg chitosan(CHS),respectively.

• 5种日粮是在基础日粮中加入0、50、100、150mg/kg的壳聚糖和50mg/kg的金霉素。