Fig. 7

Re-isolation and identification of M. hyopneumoniae from BALF of all pigs. a Growth condition and colour observation of samples re-isolated from the BALF of all pigs after 120 h of culture at 37 °C. Infected group of Bama miniature pigs (BI): BI1, BI2, BI3, BI4, BI5, BI6; Control group of Bama miniature pigs (CI): BC1, BC2, BC3; Infected group of conventional pigs (CI): CI1, CI2, CI3, CI4, CI5, CI6; Control group of conventional pigs (CC): CC1, CC2, CC3; N: KM2 culture medium of M. hyopneumoniae. b BALF cultures after colour change and pH value between 6.5–6.8 after tested were collected, and cultures among infected groups of Bama miniature pigs (BI) and infected groups of conventional pigs (CI, data not shown) were subjected to Wright’s staining and electron microscopic observation at 1000 × magnification. M. hyopneumoniae mainly displayed ring-shaped, spherical, bipolar, crescent, filamentous, and other mycoplasma-like cells. c and d Nested PCR test of P36 for re-isolated M. hyopneumoniae of passage 2 using specific outer and inner primers, respecively. M, DNA 2000 marker; P, positive control; N, negative control; Infected group of Bama miniature pigs (BI): BI1, BI2, BI3, BI4, BI5, BI6; Control group of Bama miniature pigs (BC): BC1, BC2, BC3; Infected group of conventional pigs (CI): CI1, CI2, CI3, CI4, CI5, CI6; Control group of conventional pigs (CC): CC1, CC2, CC3; the amplified product sizes of outer and inner product were 621 bp and 427 bp, respectively