鸡白痢沙门氏菌鸡胚感染模型建立方法的筛选

为筛选出理想的鸡白痢沙门氏菌宿主感染模型的建立方法，本研究通过选择不同接种方式配合不同菌液浓度接种不同胚龄鸡胚建立感染模型，将90枚SPF鸡胚随机分成9组，每组10枚，分别为A、B、C、D、E、F、G、H、I组，A组为空白对照组，其余各组为模型组，模型组分别以气室接种、蛋壳接触接种的方式对不同胚龄（11和14胚龄）SPF鸡胚接种不同浓度（1×10³、3×10³、9×10³、3×10⁵、9×10⁵ CFU/mL）的鸡白痢沙门氏菌C79-3菌株。每天观察情况直至出雏，待雏鸡孵出后按组分笼饲养，每隔12 h观察1次，连续观察7 d，观察各组雏鸡的临床症状、死亡情况，观察期结束对死亡和存活雏鸡进行剖检、组织病理学检查及鸡白痢沙门氏菌的分离鉴定。结果显示，各模型组均有雏鸡出现明显的鸡白痢病症状并死亡，相较于其他模型组，以11胚龄蛋壳接触感染方式接种9×10⁵ CFU/mL的C79-3菌液的F组和14胚龄气室感染方式接种3×10³ CFU/mL C79-3菌液0.1 mL的H组，鸡胚出壳率较高，可分别达到80%和90%，出壳雏鸡呈现明显鸡白痢病特征，剖检可见肝脏出血、盲肠膨大、卵黄囊吸收不良；组织病理切片可观察到肝脏、盲肠、心脏各有不同程度的损伤，发病率分别100%和88.8%，并且鸡白痢沙门氏菌阳性检出率分别达70%和90%。本研究结果表明，以11胚龄蛋壳接触感染方式接种0.1 mL 9×10⁵ CFU/mL的C79-3菌液和14胚龄以气室感染方式接种0.1 mL 3×10³ CFU/mL的C79-3菌液的两种方法均可用于建立稳定的鸡白痢沙门氏菌宿主感染模型。

Screening of Methods for Establishing Chicken Embryo Infection Model of Salmonella Pullorum

In order to screen the suitable method of establishing host infection model of Salmonella Pullorum, the infection model was established by inoculating chicken embryos of different ages with different inoculation methods and different concentration of bacteria solution.90 SPF chicken embryos were randomly divided into 9 groups, 10 in each group, which were divided into A, B, C, D, E, F, G, H, I groups, group A was blank control group, and the other groups were model groups.In the model groups, different concentrations of Salmonella Pullorum C79-3(1×10³, 3×10³, 9×10³, 3×10⁵, 9×10⁵ CFU/mL) were inoculated on SPF chicken embryos of different ages (11 and 14 embryo ages) by air chamber inoculation and eggshell contact inoculation.After hatching, the chicks were reared in different cages according to groups, the clinical symptoms and death of chicks in each group were observed every 12 hours for 7 days.At the end of the observation period, autopsy observation, histopathological examination and isolation and identification of Salmonella Pullorum were performed on the dead and surviving chickens.The results showed that all the chicks in each model group performed obvious symptoms of pullorum and died, and compared with other model groups, group F inoculated with 9×10⁵ CFU/mL of C79-3 bacteria in 11 embryo age eggshell contact infection and H group inoculated with 3×10³ CFU/mL of C79-3 bacteria in 14 embryo age eggshell air chamber infection had higher rate of eggshell emergence, which could reach 80% and 90%, respectively, and the shelled chicks showed obvious characteristics of pullorum dysentery.Autopsy showed liver hemorrhage, cecum enlargement and yolk sac malabsorption.Histopathological sections showed varying degrees of injury to the liver, cecum and heart, with an incidence of 100% and 88.8%, respectively, and the positive rate of Salmonella Pullorum was 70% and 90%.This study showed that the two methods of inoculating 0.1 mL 9×10⁵ CFU/mL C79-3 bacteria in 11 embryo age eggshell contact infection and 0.1 mL 3×10³ CFU/mL C79-3 bacteria in 14 embryo age air chamber infection could be used to establish a stable host infection model of Salmonella Pullorum.