The effect of tilmicosin and apramycin alone or together in treatment of experimentally infected chickens with mycoplasma gallisepticum only or with escherichia coli

Mycoplasmosis remains one of the most expensive and common diseases facing poultry industry. The presence of Mycoplasma gallisepticum (MG) predisposes birds to other infections as Escherichia coli which together causes mortality, and sub-optimal performance. Therefore, this study was carried out to evaluate the efficacy of tilmicosin, apramycin and both drugs together on experimentally infected chicken with local field isolates of MG only or with E. coli as CRD and CCRD treatments. The present investigation clarified that infected groups treated with both tilmicosin and apramycin showed additive or synergistic interaction between them, which in turn confirmed the safety use of this combination therapy. The use of the recommended therapeutic dose of tilmicosin (1ml/L) or apramycin (0.5gm/L) alone or in combination for 5 successive days after appearance of the clinical signs are of considerable value in the treatment of MG infection in broiler chickens as antimycoplasmal drugs through displayed valuable improvement in clinical symptoms, survival rate, lesion scoring and termination of infection by the mycoplasmacidal effect of both drugs. The results also indicated that combined tilmicosin-apramycin therapy as antimicrobial drugs gives relatively stable results in the treatment of CCRD in chickens with a superior activity and efficacy than apramycin or tilmicosin alone followed by apramycin in reducing the severity of lesion, mortality rate, E. coli count and improve the general activity of chickens, so it can be used as alternative strategy that may contribute to the treatment programs of CCRD. Co-infected group treated with tilmicosin showed less improvement than other MG and E. coli infected treated groups this returned to its restricted effect on E. coli infection