Pathogenicity and effect of exogenous antibodies on the viability of Mycoplasma gallisepticum in chicken embryos

Isolation of mycoplasma gallisepticum (mg) was attempted from different organs including trachea,air sacs and lungs (n=27 for each organ) of commercial layer chickens. out of all the organs examined,18.51% trachea (n=5/27) and 7.41% air sacs (n=2/27) were found positive for mg isolates; whereas,no isolation was made from lungs. the isolates were identified by microbiological and biochemical tests i.e. change in the color (red to orange) and turbidity of broth in addition to the typical colony characteristics (fried egg shaped colonies) of mg on pplo (pleuropneumonia like organism) agar. isolates were purified and sub-cultured in pplo broth and pathogenicity of mg was observed in chicken embryos on the basis of mortality pattern. gross pathological lesions in inoculated chicken embryos included oedema,stunted growth and hemorrhagic embryos. in second trial,antigenantibody complex was inoculated in 7-days old (n=10) embryonated eggs to observe the effect of the exogenous antibodies on the viability of mg in chicken embryos. results showed that simultaneous administration of anti-mg antibodies along with mg antigen failed to neutralize the antigen inside the embryonated chicken eggs.