Research Article
Mohamad T Farran, Majd G Kais,
Abstract
This study aimed at the determination of 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. A total of 108 sixteen-weeks-old breeder pullets of the ROSS 308 strain were subdivided equally into 6 groups. Pullets of group 1 remained unvaccinated and untreated with PAC. Birds of groups 3, 4, 5 and 6 were vaccinated with AviPro® MGF at 16 weeks of age and treated with PAC at 3, 7, 14, and 21 days post-vaccination respectively. Group 2 was kept as the vaccinated non-treated group. The pullets were tested for the presence of MGF strain in the trachea at different days after PAC-treatment completion. All PAC-treated groups showed tracheal MG recolonization after the treatment was discontinued. The percentage of positive tracheal MG swab cultures was consistently higher in group 6, reaching a plateau at 14 days post PAC treatment (100%, P<0.05). qPCR implied-tracheal MG counts indicated better recolonization efficiency for birds of groups 5 and 6 reaching up to 2322 × 103 and 2839 × 103 cfu/ml of broth, respectively, at 35 days post PAC treatment. Moreover, Group 6 showed the significantly highest titer to MG, recording a value of 2160, followed by the vaccinated untreated Group 2 (1128). For a successful application of live MG vaccine/antibiotics combination, it is recommended to delay PAC treatment 21 days after the vaccination of breeder pullets with AviPro® MGF.