Laboratory Diagnosis of Mycoplasma gallisepticum (MG) Infection in Experimental Layer Chicken Receiving MG Vaccines and MG Organisms

Abstract

This experiment was designed to study the results of laboratory diagnosis of Mycoplasma gallisepticum (MG) infection in layer chicken receiving MG vaccines and MG organisms. One hundred and twenty 1-day-old-malelayer
chickens were raised in separate isolation rooms and equally allocated into 4 separated groups. When 4 weeks old, groups 1, 2, 3 and 4 served as a negative control, a MG commercially inactivated vaccine group, a MG commercially live vaccine group and a MG infected group, respectively. In each group, ten birds were swabbed and bled when 4, 5, 6, 7, 8, 9 and 11 weeks old. Swab samples were tested for MG Infection by culture and polymerase chain reaction (PCR) procedures. Sera were determined for MG antibody responses by a serum
plate agglutination (SPA) test and by 2 commercial enzyme-linked immunosorbant assay (ELISA) test kits, IDEXX®and Synbiotics®. Results revealed that MG organisms were only found in groups 3 and 4 using
culture and isolation when 5 and 11 weeks old, and by PCR during the 5 to 9 week old period. The SPA results showed positive reactors in groups 3 and 4 during the 7 to 11 week old period. The positive reactors detected
by both commercial ELISA test kits were similar, detecting MG antibody responses in groups 3 and 4 during the 7 to 11 weeks old period. However, only group 2 found positive reactors by the Synbiotic® ELISA test
kits, during the 9 to 11 week old period.