Evaluation of broiler breeder flocks for nonspecific Mycoplasma synoviae reaction

Serums from 65 broiler breeder flocks were evaluated for mycoplasma synoviae (MS) and Mycoplasma gallisepticum (MG) antibodies by serum plate agglutination (SPA), micro hemagglutination-inhibition (HI), and agar gel precipitin (AGP) tests. The nonspecific SPA reaction in serum from breeder flocks was eliminated by diluting the serum 1:5 in phosphate-buffered saline (PBS), pH 7.2, before testing provided that the MS antigen reacted with 1:10 dilution of the MS antiserums. The nonspecific SPA reaction was confirmed by negative HI and AGP reactions. Wehn specific MS reactions occurred, the serums showed a micro HI titer of 1:80 or greater and an AGP line, and MS was isolated from the upper respiratory tract of infected birds. Serums from experimental birds on Aureomycin, 200 g/ton of feed, were positive on the SPA test but were negative for micro HI and AGP tests. MS was isolated from these birds. Nonspecific SPA MG reaction occurred in many of the flocks which were negative by MG HI and AGP tests.