Abstract

This survey was carried out to determine the seroprevalence of Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS) infections in commercial layer farms in Centernorth of Iran. A total of 2000 serum samples were collected from 40 commercial layer flocks (50 samples/ flock) mostly > 40-week-old. Sera tested by serum plate agglutination (SPA) method using commercial MG antigen and MS antigen. Positive reactions retested by SPA on 1:8 dilution and the flocks with more than 10% positive reactions considered positive serologically. The results showed that 4 of 40 (10%) flocks were MG positive and the rest (90%) were negative. About MS, 17 of 40 (42.5%) flocks were positive and 33 of 40 (57.5%) were negative. Sera tested for MG were: 125 of 2000 (6.25%) positive, 1821 of 2000 (91.05%) negative and 54 of 2000 (2.7%) suspect. Sera for MS were: 371 of 2000 (18.55%) positive, 1617 of 2000 (80.85%) negative and 12 of 2000 (0.6%) suspect. Statistical analysis showed a positive correlation between MS positive flocks and strain (LSL flocks compared to Hy-Line flocks) and capacity of the farms significantly (P<0.05). It seems that the seroprevalence of MS in the commercial layer flocks of the Centernorth of Iran is high.

Key words: Mycoplasma gallisepticum, Mycoplasma synoviae, seroprevalence, serum plate agglutination test.