Serological Detection And Pathogen Identification Of Avian Mycoplasmosis In Some Areas Of Shanxi Province

Avian mycoplasmosis(mainly including Mycoplasma gallinarum and Mycoplasma synoviae)is a widespread and difficult to eradicate infectious disease in chicken industry.It often brings some side effects to chicken,such as prolonged feeding period as well as decreased the ratio of egg laying fertilization and hatchability leading to a great economic losses to the chicken breeding industry.To understand the prevalence of Mycoplasma gallisepticum and Mycoplasma synoviae in some areas of Shanxi Province,chicken serum samples was collected to analysis of the antibody against the pathogens by serum plate agglutination test(SPA).Duplex PCR method was further performed to verify the suspected infections.Then,the positive samples were cultured to isolate and purify pathogens in vitro by conventional identification method.Finally,the sequences 16 S r DNA genes of Mycoplasma cultures were analyzed by homology and genetic evolutionary tree analysis to understand the prevalence of Mycoplasma gallinarum and Mycoplasma synoviae strains in some areas of Shanxi Province and to prepare for further prevention and treatment.In this trial,1325 chicken serum samples were collected from 15 farms in Taiyuan city(x)and Xinzhou city(15-x).The results showed that the average antibody positive ratio of Mycoplasma gallinarum and Mycoplasma synoviae was 36.3% and 17.7%,respectively,and the positive ratio of both antibodies was 1.4%.The duplex PCR method was established to detect 43 tissue samples of suspected Mycoplasma gallinarum infection.The results indicated that 10 of them were positive for Mycoplasma gallinarum,3 of them were positive for Mycoplasma synovialis,and 1 samples was detected both Mycoplasma gallinarum and Mycoplasma synoviae,respectively.The positive samples were isolated and cultured in vitro.The results showed three of Mycoplasma gallisepticum and two of Mycoplasma synoviae strains were isolated and purified by the routine identification.Finally,based on the sequences of 16 S r DNA gene and genetic evolution tree analysis,it is concluded that three strains of Mycoplasma gallinarum isolated from Shanxi Province belong to the same evolutionary branch as the international standard strain MG-S6,and two strains of Mycoplasma synoviae belong to the same evolutionary branch as MS-CHN-WF224-2016 and MS-CHN-SQ27-2007 isolated from Henan province.To sum up,the infections of Mycoplasma gallinarum and Mycoplasma synoviae in some parts of Shanxi province is serious.There are many kinds of Avian mycoplasmosis strains and the situation is complex.Once infected,it is difficult to clear the pathogen.Moreover,the use of Mycoplasma gallinarum and Mycoplasma synoviae vaccines is not universal in Shanxi.The long-term misuse of antibiotics will lead to the emergence of drug-resistant strains chicken farms in various places should not only strengthen vaccination,but also make biosafety measures.