Molecular identification and cross-immunogenic study on two field isolates of Mycoplasma synoviae isolated from broilers in five districts of Khyber Pakhtunkhwa

Background: Mycoplasma synoviae (MS) is an important poultry pathogen causing heavy economic losses Worldwide. Subclinical persistence of this pathogen is the major issue to control its prevalence.Aim: This study aimed to determine the molecular and cross-immunogenicity of MS among broilers in five Districts of Khyber Pakhtunkhwa (KP).Methods: This study was conducted by collecting 434 specimen samples from 40 broiler farms and desi poultry in five districts of KP. Specimen samples from the broiler birds (n = 150), broiler farm environment (n = 264), and desi poultry birds (n = 20) were aseptically collected and serially passaged in Modified Frey's broth. The homologous and heterologous antibody reactions were studied in rabbits. Before inoculation into rabbits, the MS isolates were inactivated by formalin and adjuvanted with Montanide.Results: The overall turbidity prevalence in Frey's broth was observed as 109/434 (25.11%) samples, and these turbidity -positive samples were shifted on Frey's agar. After the appearance of classic fried egg colonies, the Biochemical confirmation was supported by the production of catalase and phosphatase, reduction of tetrazolium, film and spot assay, and fermentation of glucose for species differentiation in avian mycoplasma. The MS prevalence percentage was recorded as 2% (9/434) through biochemical tests. The PCR results showed 0.5% MS prevalence with two field isolates (named MS-1 and MS-2). Both MS-1 and MS-2 field isolates showed similar values (42.2) of homologous geometric mean titer (GMT). While the heterologous GMT for MS-1 serum against MS-2 isolate was lower (27.9) as compared to MS-2 serum against MS1 isolate (38.9). No titer was detected in the control group (Group-III).Conclusion: In conclusion, the results indicated the existence of MS in broiler birds and high homologous titers recorded between field isolates, which is a perpetual menace to poultry.