However, the activity declined significantly from the third passage on (Fig. 1). Figure 1 Transformation of DON to DOM-1 by the subcultures of digesta samples . The digesta samples were from the large intestine of chickens fed clean or DON-contaminated wheat (10 μg g-1 DON) during the in vivo enrichment experiment. The subcultures were grown in L10 broth containing 100 μg ml-1 DON. Each subculture was incubated for 72 hours. n = 6. Selection for DON-transforming

bacteria When individual antibiotics were tested for bacterial selection (Step EX 527 3 in Fig. 2), virginiamycin, lincomycin, and tylosin showed no detrimental effect on either the activity of DON transformation or bacterial growth of the start cultures at all tested concentrations NVP-BGJ398 (Table 1). However, a similar effect was observed only at the low concentration (5 μg ml-1) of streptomycin, penicillin G, and salinomycin. Different combinations of these antibiotics were then investigated for their effect on supporting the activity of DON transformation and the growth of bacterial cells. Only one combination containing virginiamycin

(20 μg ml-1), lincomycin (60 μg ml-1), and salinomycin (5 μg ml-1) significantly reduced the growth of bacterial cells without detrimental effect on the DON-transforming activity. Hence, the cultures selected through this combination were used for further selection by the AIM+CecExt medium. Table 1 Effects of antibiotics on the growth and DON-transforming activity of bacteria from the large (LIC) or small (SIC) intestine. Antibiotics Final ACY-1215 purchase concen (μg/mL) LIC-S2   LIC-S3   SIC-S2   SIC-S3       Growth DON to DOM-1 (%)     Growth DON to DOM-1 (%)     No antibiotic 0 +++ 100.0 N/A   +++ 100.0 +++ 100.0 Streptomycin 100 +++ 49.3 +++ 25.6 +++ 44.3 +++ 5.8   50 +++ all 100.0 +++ 30.8 +++ 48.7 +++ 11.4   5 +++

100.0 +++ 100.0 +++ 100.0 +++ 100.0 Gentamicin 80 +++ 18.1 +++ 6.0 ++ 44.0 +++ 7.1   40 +++ 23.5 +++ 6.5 +++ 44.8 +++ 7.4   5 +++ 100.0 +++ 22.5 +++ 46.5 +++ 6.8 Bacitracin 60 ++ 16.2 ++ 0.0 +++ 45.0 +++ 8.0   30 ++ 16.1 ++ 2.5 +++ 45.0 +++ 8.8   5 +++ 15.8 +++ 3.9 +++ 47.0 +++ 11.9 No antibiotic 0 +++ 100.0 +++ 100.0 +++ 100.0 +++ 100.0 Penicillin G 100 + 12.1 +++ 1.5 ++ 100.0 + 35.5   50 + 12.7 +++ 7.4 ++ 100.0 + 44.1   5 ++ 100.0 +++ 100.0 +++ 100.0 +++ 100.0 Virginiamycin 20 +++ 100.0 +++ 100.0 +++ 100.0 +++ 100.0   10 +++ 100.0 +++ 100.0 +++ 100.0 +++ 100.0   5 +++ 100.0 +++ 100.0 +++ 100.0 +++ 100.0 Lincomycin hydrochloride 60 +++ 100.0 +++ 100.0 +++ 31.3 +++ 3.6   30 +++ 100.0 +++ 100.0 +++ 100.0 +++ 100.0   5 +++ 100.0 +++ 100.0 +++ 47.3 +++ 100.0 No antibiotic 0 +++ 100.0 +++ 100.0 +++ 100.0 +++ 100.0 Salinomycin 80 +++ 16.7 +++ 2.0 +++ 55.2 +++ 8.9   40 +++ 18.0 +++ 4.0 +++ 89.2 +++ 80.9   5 +++ 16.8 +++ 100.0 +++ 100.0 +++ 100.0 Vancomycin 30 +++ 15.9 +++ 2.5 ++ 46.2 +++ 9.6   15 +++ 15.0 +++ 2.2 ++ 44.9 +++ 10.5   5 +++ 38.5 +++ 13.2 ++ 46.8 +++ 9.7 Carbadox 50 +++ 16.4 ++ 3.5 ++ 27.7 +++ 3.9   25 +++ 100.