ACID AND BILE TOLERANCE OF LACTOBACILLUS ISOLATED FROM CHICKEN INTESTINE

Twelve Lactobacillus strains isolated from chicken intestine were used to investigate acid and bile tolerance in vitro. Ten out of the 12 st rains were slightly affected by 0.3% bile salts, showing a delay of gr owth (d) of 0.6-37.2 min compared with growth in control cultures. Two strains were not affected by the bile salts, Of the 12 strains, seven could be arbitrarily classified as resistant (d < 15 min) and five as tolerant (15 min < d less than or equal to 40 min). Lactobacillus str ains from the caecum showed better tolerance to acid than those from t he ileum. Generally, the survival of the ileal strains was very low at pH 1.0 and 2.0, and moderate at pH 3.0. In contrast, caecal Lactobaci llus strains could survive at pH 1.0 for up to 2 h of incubation; grow th was moderate at pH 2.0 and good at pH 3.0 and 4.0.