Combination of live vaccine and Pulmotil-AC in control of Mycoplasma gallisepticum in breeder pullets.

Abstract

This study aimed to determine the optimal time interval between the vaccination with a live Mycoplasma gallisepticum vaccine AviPro® MGF and the administration of the antibiotic Pulmotil® AC (PAC) to broiler breeder pullets while preserving the vaccine efficacy by studying the Mycoplasma gallisepticum F-strain (MGF) re-population pattern in the vaccinated birds after the PAC treatment was completed. A total of 108 sixteen-weeks-old breeder pullets of the ROSS 308 strain were subdivided equally into 6 treatments of 18 birds. Pullets of treatment 1, the control, remained unvaccinated and deprived of Pulmotil® AC. Birds of treatments 3, 4, 5 and 6 were vaccinated with AviPro® MGF at 16 weeks of age via drinking water and administered Pulmotil-AC as per the manufacturer recommendation at 3, 7, 14, and 21 days post-vaccination. Treatment 2 was kept as the vaccinated PAC-deprived group. The pullets were tested by serology (ELISA) and quantitative PCR for the presence of MGF strain in the trachea at different days after the PAC treatment completion namely at 3, 7, 14, 21, 28 and 35 days post vaccination. All PAC-treated groups were showing tracheal MG recolonization after the antibiotic administration was discontinued, which indicates that the Mycoplasma strain of AviPro® MGF endures Pulmotil® AC treatment. The percentage of positive tracheal MG swab cultures was consistently higher in treatment 6, reaching a plateau at 14 days post PAC treatment discontinuation (100percent, P 0.05). These results were further reflected by the tracheal MG CFU counts which indicated better recolonization efficiency for birds of treatments 5 and 6 reaching up to 2322 × 10³ and 2839 × 10³ cfu-ml of broth, respectively at 35 days post PAC treatment discontinuation. ELISA test showed low titers indicating that the immunogenicity was not high enough to trigger abundant IgG production in all treatments. However, treatment 6 showed the significantly highest titer, recording a value of 2160,