Evaluation of Inactivated Mycoplasma gallisepticum Oil-Emulsion Bacterins for Protection against Airsacculitis in Broilers

Abstract

Broiler chicks were vaccinated subcutaneously in the neck at various ages with a single 0.5-ml dose of beta-propiolactone-inactivated Mycoplasma gallisepticum (MG) oil-emulsion bacterin. Four weeks later, vaccinated and control chicks were placed in cold environmental cabinets, infected with infectious bronchitis virus intratracheally, and 2 days later challenged by aerosol exposure to live MG broth culture. All chicks were killed 21 days later and scored postmortem for the rate and severity of airsacculitis produced in each group. Broiler chicks vaccinated at 1 day of age had only slight protection against the development of airsacculitis. Results were variable when chicks were vaccinated at 7 days of age, with little evidence of resistance to airsacculitis. However, when broiler chicks were vaccinated with MG bacterins at 11 to 15 days of age, they acquired significant protection against airsacculitis compared with controls. Viable MG organisms were readily isolated from most of the sampled tracheas and air-sac lesions cultured 21 days post-challenge, indicating a lack of protection against infection of the respiratory tract. MG-vaccinated chicks generally produced antibodies readily detectable by the rapid serum-plate test, tube-agglutination, and hemagglutination-inhibition (HI) tests. Some of the vaccinated chicks, but none of the unvaccinated control chicks, developed positive reactions to agar-gel-precipitin tests following challenge. Low HI titers at challenge were not necessarily indicative of lack of protection against the development of airsacculitis, since good protection was often observed in chickens with low to moderate HI titers.

The effect of vaccination with a bacterin on the horizontal transmission ofMycoplasma gallisepticum

“…However, the analysis of the M. gallisepticum levels showed that the logarithm of the AUC in the vaccinated pairs was 0.51 Table 1. Q-PCR and serology results of the non-vaccinated and vaccinated groups Although this is first report where the horizontal transmission of M. gallisepticum among vaccinated birds has been quantified, the indication of a reduction in M. gallisepticum shedding is in agreement with earlier studies (Hildebrand et al ., 1983;Yoder et al ., 1984;Kleven, 1985;Talkington & Kleven, 1985;Withear, 1996). This finding prompted several authors to hypothesize that vaccination might have a long-term effect, eventually stopping horizontal transmission (Talkington & Kleven, 1985;De Nie & Goren, 1989).…”

An inactivated temperature‐sensitivemycoplasma gallisepticummutant for protection against airsacculitis

“…An experimental inactivated oil emulsion MG bacterin prepared by Yoder et al (1984) was also capable of protecting 11-to 14-day-old chickens against experimental challenge. Our present TS MG vaccine with adjuvant was effective as well.…”

“…Chickens inoculated with vaccine emulsified in adjuvant all developed a high level of antibody (Panigrahy et ah, 1981;Hildebrand et al, 1983;Glisson and Kleven, 1984;Yoder et al, 1984). However, the titres of serum antibody and the levels of protection might not be related (McMartin and Adler, 1961;Hayatsu et al, 1974;Lam and Lin, 1984b).…”

“…Intranasal inoculation was more successful than intramuscular administration (Hayatsu et al,191 A). Age of the chickens at vaccination was also found to be important (Yoder et al, 1984); there was little or no protection in chickens vaccinated with MG bacterin at 7 days of age or younger, but there was significant protection in chickens inoculated with the same vaccine when 11 to 15 days of age. Furthermore giving the bacterin without adjuvant had little or no success in protecting chickens (Hayatsu et al, 1974), whereas bacterin with adjuvant afforded significant protection (Hildebrand et al, 1983;Yoder et al, 1984).…”

Studiesin vivoon the efficacy of enrofloxacin againstMycoplasma gallisepticum

“…The pathological lesions in the air sac were evaluated according to the scoring system described by Yoder et al (1984).…”