陕西某种鸡场大肠埃希菌血清型调查与灭活苗研制

为控制大肠埃希菌病的危害,对从陕西某种鸡场分离鉴定的20株鸡大肠埃希菌进行了血清型调查,结果O2型5株、O6型3株、O78型4株,未定型8株,表明鸡场的大肠埃希菌有了新的流行菌株O6出现。用定型的分离菌株研制的自家灭活菌苗免疫接种雏鸡,7 d后可检测到抗体,14 d产生免疫保护力。29日龄二免,90 d后抗体水平仍在5log2以上。119日龄三免,免疫后5个月抗体水平仍维持较高,但6个月后,抗体水平已在5 log2以下,失去保护力。通过3年的应用,该场种鸡大肠埃希菌病的平均死亡率由6.7%下降至1.6%,雏鸡死亡率由4.2%下降至1.8%,差异极显著(P<0.01)。

E. Coli Serotype Investigation and Preparation of Inactivated Vaccine in a Stud Layer Farm of Shaanxi Province

In order to control chicken E.coli,the serotype was investigated in 20 strains of chicken E.coli which were isolated from a spectes layer farm in Shaanxi province.The results showed that the serotypes of E.coli were O2,O6,O7.There were new serotype strains appearing that was O6.The self-inactive vaccine were prepared with 3 tipical serotype E.coli that had been identified.It was applyed to vaccinate chickens and the antibody coulde be determined 7 days after immunization,and produced protection effect 14 days after immunization.Then it was used to vaccinate chickens in 29 days old the second time,90 days after the second immunization,the antibody level coulde be maintained upward 5 log2.The third immunization was in 119 days old and the antibody level coulde be maintained higher in 5 months after immunization.Only 6 months later,the antibody level was under 5 log2,and its protection effect was after using vaccination for 3 years,the average mortality of E.coli in stud layers was from 6.7% down to 1.6%,and in chicks from 4.2% down to(1.8%,)significant difference(P<0.01).