四株鸡毒霉形体菌株对SPF鸡胚的致病作用

PATHOGENICITY OF FOUR STRAINS OF Mycoplasma gallisepticum(MG) IN SPF CHICKEN EMBRYOS

将MG不同菌株的培养物，经卵黄囊接种SPF鸡胚，结果各菌株均能使鸡胚发生死亡，总死亡率在接种后3～13d内达82％，死胚经病变检查，菌检和分离物的血清学鉴定，证实系感染MG所致。测定了MGIc1菌株的不同接种量对鸡胚死亡的影响，发现它们之间没有很密切关系。在SPF源鸡体上致病力低下的二株MG菌株的鸡胚致死率为60％～90％，反映出同一菌株对鸡体和鸡胚的致病力有差异。从部分死胚的卵黄、卵黄囊、绒毛尿囊膜和尿囊液中分离到MG，并测定了这些部位MG的含量。根据实验结果，认为SPF鸡胚人工感染MG，具有比SPF源鸡体更敏感、所需试验条件简单、恒定、因果关系明确的优点，可以作为测试MG菌株某些性质的一种模型。

SPF chicken embryos were inoculated with cultures of four MG strainsthrough yolk sac. As a result, all the four strains could kill chicken embryos, the totalmortality rate within 3 ~ 13 days after inoculation attained 82%. The results of lesionexamination, microbiological and serological test of isolates for the dead embryosdemonstrated that the dead embryos had died from MG infection. The effects of differentinoculation levels of MG Ic1 strain were determined, no highly close relations were foundbetween them. For the two MG strains having poor pathogenicity in SPF chicken body,theirembryo-killing rates were 60%~ 90%, this reflected that for the same strain, itspathogenicity in chicken body differed from that in chicken embryo. MG isolates wereobtained from the yolks, yolk sacs, allantochorions, allantoic fluids and embryo bodies ofsome of the dead embryos and the MG contents at these sites were determined. According tothe experimental results, it is considered that the mode of artificially infecting SPF chickenembryos with MG has the following advantages:the SPF chicken embryos are more sensitivethan the SPF chicken, the test conditions are more simple, constant and the relationshipbetween cause and effect is more cIear; so this mode can be used for determining certaincharacters of MG strains.