Figure 4

PCR-DGGE bacterial profiles showing the richness of bacterial populations . A) Bacterial profiles before and after antibiotic treatments. Lane 1: large intestinal digesta sample (LIC); Lane 2: start culture that was the first subculture from the digesta (LIC) before lincomycin treatment; Lanes 3 and 4: same start culture after the treatment with lincomycin at 60 and 30 μg ml^-1, respectively; Lanes 5 and 6: same start culture after the treatment with tylosin at 80 and 40 μg ml^-1, respectively. B) Changes of PCR-DGGE bacterial profiles through the selection by antibiotics and AIM+CecExt medium. Lane 1: start culture (1^st subculture from the digesta) before antibiotic and AIM+CecExt treatments; Lane 2: the same culture (in Lane 1) after antibiotic and AIM+CecExt treatments; Lane 3: a pure culture of a single colony isolate with DON-transforming activity (Isolate LS-61). Note: Lane 1, lanes 2 - 4, and lanes 5 - 6 of Panel A were from three separate DGGE gels. The migration of their DNA bands was not identical among the different gels.