Control of Mycoplasma gallisepticum Infection in Commercial Broiler Breeder Chicken Flocks Using Tilmicosin (Provitil Powder®) Oral Formulation

Abstract

Despite the great efforts poultry breeding companies made towards eradication of pathogenic mycoplasmas from poultry flocks, Still Mycoplasma gallisepticum (MG) infection is of continuing economic concern in commercial broiler breeder chicken flocks. Control of MG infection in broiler breeder chicken flocks by chemotherapy is the most practical way to minimize economical losses. Tilmicosin is one of the most important antimicrobial agent used for treatment and control of MG infection. This study was carried out on eight broiler breeder chicken flocks with a history of MG challenge {signs, post mortem, and serology [enzyme linked immunosorbent assay (ELISA)]}. Tilmicosin (Provitil powder^® 30 mg/kg body weight) was used to limit MG infection in these flocks, and was given to birds for 3 successive days every 5 weeks for 4 months. 136 serum samples were collected from these flocks (16-18 samples per flock) before starting tilmicosin treatment and the same number of serum samples were collected following each three treatment course at 5 weeks interval. Mycoplasma gallisepticum ELISA was performed on these samples for the purpose of detecting MG antibodies in these flocks and analyzing data subsequently. The first and second course of tilmicosin treatment did not have any significant effect on MG ELISA results (GMT) (P>0.05), while after the third course, GMT had dropped significantly (P< 0.05) in all tested flocks compared to results gained prior starting treatment with tilmicosin. The overall sero-prevalence of MG in broiler breeder chicken population involved in the study was 80.43% and 44.09% before and after completing medication with tilmicosin respectively, while the percentage of antibody positive chickens among flock samples ranged from 38.88-100% and 18.75-56.25% before and after complete medication with tilmicosin respectively (P< 0.05). Improvement in reproductive performances was observed (decreased mortality, increased feed intake and increased egg production and hatchability). The overall data presented here indicated that Provitil^® (30 mg/kg body weight for 3 successive days every 5 weeks for 4 months) is considered a highly effective therapeutic in MG control programs for broiler breeder chicken flocks, and has a net positive effect for the producer. Further studies are necessary to assesses economic losses due to MG and the cost benefit of countermeasures.