Abstract: The Mycoplasma ovipneumoniae (MO) SC01 isolates were cultured in the modified Thiaucourt's medium and collected in different times. The growth curve of MO was determined by the color change unit (CCU), nephelornetry and Real-time PCR. The results of CCU showed 0 to 4 h was the lag phase, 4 to 16 h was logarithmic phase and the most of lg CCU/mL was 10.7000?0.4700, 16 to 20 h was the stationary phase, and 20 h later was decline phase of SC01 isolates. The results of nephelornetry method showed that D_{420 nm} of five folds concentration of SC01 cultures gradually increased with the culture time, following the 0.0028?0.0002 in 2 h, slowly increased in 4 to 12 h, fast increased in 12 to 24 h, the 0.8609?0.0045 of highest level in 24 h and then stabilizaed. The results of Real-time PCR showed that the copy of SC01 isolates steadily increased in 2 to 30 h that the lg copy/mL was 4.5889?0.0048 in 2 h and the most of lg copy/mL was 7.6165?0.1089 in 30 h. Furthermore, the correlation analysis exhibited that, in lag phase and logarithmic phase, the CCU had a high correlation with the Real-time PCR and nephelornetry, and Real-time PCR also existed a high correlation with nephelornetry, following that the correlation coefficients were 0.967,0.720 and 0.849, respectively. During 2 to 30 h,there was a high correlation between the Real-time PCR method and nephelornetry and the correlation coefficients was 0.912. Based on the above results of the time and accuracy of three detection methods, the study indicated that the Real-time PCR method was fast, accurate and easy to standardization and could replace for the CCU and nephelornetry methods.

Key words: Mycoplasma ovipneumoniae (MO); color change unit(CCU); nephelornetry; Real-time PCR