【摘要】 本试验将 30只MG阴性的 2 0周龄的蛋种鸡随机分为 4组 ,Ⅰ组于 2 1和 2 5周龄、Ⅱ组仅于 2 5周龄时分别颈部皮下接种MG油乳剂灭活苗 0 5ml/只 ,Ⅲ组于攻毒后 1周接种 1ml/只 ,另设一组对照 ,不接种疫苗。各组均在 2 9周龄时用通过SPF鸡两次复壮的MG BG4 4T株经左胸气囊和鼻腔攻毒。收集攻毒后 1～ 7周内所产的蛋 ,用PCR方法检测鸡蛋卵黄膜中的MG。结果在攻毒后 7周内各免疫组 (Ⅰ、Ⅱ、Ⅲ )的垂直传播率显著低于对照组 (P<0 .0 1) ,分别比对照组低 2 6 37%、12 8%、13 6 4 %。攻毒后各免疫组和对照组经 4次采样均可从喉头拭子中分离到MG但免疫组的分离率较低。攻毒后第 7周从对照组鸡的气管、肺、气囊中均可分离到MG ,而试验Ⅰ组仅在气管和肺中分离到了MG。试验Ⅰ组和对照组鸡的输卵管、心、肝、脾和肾中均未分离到MG。更多还原

【Abstract】 twenty week old breeding hens negative for MG were divided into four groups randomly.Group I at 21 and 25 weeks of age and Group Ⅱ only at 25 weeks of age were vaccinated subcutaneously in the nape of the neck with 0 5 ml of MG oil emulsion bacterin respectively.Group Ⅲ was vaccinated with 1ml bacterin at 1 week postchallenge(PC) and the left group unvaccinated as control.All the groups of hens were challenged by the left thoracic air sac and the nasal cavity at 29 weeks of age with the broth culture of pathogenic BG44T strain of MG,which had been transferred 2 times through SPF chickens.The eggs of all the groups from 1 to 7 weeks PC were collected and the MG were detected rapidly in the vitelline membrane of eggs by PCR.The results showed that the rates of MG vertical transmission in all the vaccinated groups(Ⅰ,Ⅱ,Ⅲ)were significantly lower than that of the unvaccinated group within 7 weeks PC namely 26 37%,12 8% and 13 64% lower respectively. From 1 to 7 weeks PC MG could be isolated from laryngeal swabs in all the vaccinated groups and the unvaccinated,but the isolation rate was lower in the former.7 weeks PC MG could be isolated from trachea,lung and air sac in the control group,while in Group I MG was isolated only from trachea and lung.MG was not found from oviduct,heart,liver,spleen and kidney in Group I and the control group.更多还原