PRELIMINARY DATA ON EFFICACY OF MYCOPLASMA-GALLISEPTICUM VACCINES CONTAINING DIFFERENT ADJUVANTS IN LAYING HENS

Chickens were vaccinated subcutaneously twice, at 13 and 17 weeks of age. The vaccines used were the whole organisms of Mycoplasma gallisepticum (MG) adjuvanted with multilamellar positively charged (MPC) liposomes or oil-emulsion. Other chickens received the same bacterins but supplemented with Salmonella typhimurium cell wall protein mitogen (STP) (50 μg/dose). At 21 weeks of age, each bird was challenged in the right and left caudal thoracic air sacs. The challenge dose/chicken was 1.3 × 105 CFU of MG (R-strain). A significant immunoglobulin (Ig) response specific to MG was observed in sera of chickens collected 3 weeks after the first and second vaccination with MG adjuvanted with MPC liposomes or oil-emulsion. The same two treatments had highly significant MG-titers in eggs collected during the first and second month post challenge. Both groups had highly significant protection (P < 0.05) against MG transmission in eggs layed during the first month post challenge. Vaccination with MG organisms adjuvanted to MPC liposomes or oil-emulsion resulted in higher egg production, during the first month following challenge, in comparison to the unvaccinated-challenged birds; the same two groups had higher egg production in the second month following challenge compared to unvaccinated-challenged birds, but not significantly different (P > 0.05). The addition of STP to bacterins containing MG organisms adjuvanted to MPC liposomes or oil-emulsion, resulted in a significant reduction (P < 0.05) of the Ig-specific to MG in sera and in a significant drop in egg production (P < 0.05) during the first month following challenge. © 1990.