鸡新城疫-禽流感二联灭活疫苗免疫不同日龄商品肉鸡的效果比较

使用鸡新城疫-禽流感（H9N2 HP株）二联灭活疫苗分别免疫3、7、14日龄三组商品肉鸡各40羽，同时设一组空白对照组。各免疫组及对照组于3、7、14、21、28、35、42日龄采血检测新城疫、禽流感抗体，于21、28、35日龄进行禽流感病毒攻毒，对比不同日龄免疫组的抗体消涨情况及不同日龄禽流感攻毒结果。发现对照组随鸡日龄增加，新城疫与禽流感抗体逐渐下降，在42日龄时下降至0，而不同免疫组新城疫与禽流感抗体均先下降，21日龄左右开始上升，至35日龄新城疫与禽流感抗体升至6log2以上。3日龄免疫组的禽流感免疫保护效果最好，21、28、35日龄时禽流感强毒攻毒保护率均达100%；7日龄免疫组在21、35日龄时禽流感强毒攻毒保护率均达100%，28日龄时禽流感强毒攻毒保护率达70%；14日龄免疫组在28、35日龄时禽流感强毒攻毒保护率均达100%，21日龄时禽流感强毒攻毒保护率只达30%。试验表明，商品肉鸡选择3日龄免疫鸡新城疫-禽流感（H9N2 HP株）二联灭活疫苗时禽流感免疫保护效果最好，采用3日龄免疫程序可以提高新城疫与禽流感的免疫保护效果，减少养殖业的经济损失。

Comparision of immune effects of bivalent inactivated vaccines containing newcastle disease virus and avian influenza virus in different days of commercial broiler chickens

3,7,14-day-old forty commercial broiler chickens were respectively inoculated with bivalent vaccines containing inactivated Newcastle disease virus(NDV) and avian influenza virus(AIV) and simultaneously, chickens were mock inoculated as control group. In order to detection antibodies against NDV and AIV, blood samples were collected from 3, 7, 14, 21, 28, 35 and 42-day-old chickens in both immune groups and control groups, and 21, 28 and 35-day-old chickens were infected with AIV, respectively. Antibody levels against NDV and AIV, as well as mortality of each group were detected for comparative analysis.The results showed that antibodies a-gainst NDV and AIV in control group represented an gradual decline as days went, till to zero on 42th day, antibody levels of immune groups decreased in the early stage, and began to increase since 21th day, ending up with 6log2 on 35th day. Immune protection effect of 3-old-day immune group was the best and protection rate against AIV reached 100 percent on 21, 28 and 35-day-old chickens. Protection rate of 7-old-day immune group was 70%on 28-day-old and that of 14-old-day immune group was 30%on 21-day-old. In conclusion, better immune protection against AIV was obtained from commercial broiler chickens inoculated with bivalent vaccine containing inactivated NDV and AIV on 3-day-old, which could improve immune protection effect against NDV and AIV and reduce economic losses of poultry industry.