Survival of bifidobacterium animalis subsp. lactis OPB-1 in the gastrointestinal tract after its administration in a milk-free soybean product and the effect on fecal microbiota in healthy adults

Abstract

The survival of Bifidobacterium animalis subsp. lactis OPB-1 in the gastrointestinal tract after its administration in a milk-free yogurt-like soybean product and effects on fecal microbiota in humans were determined. Twelve healthy volunteers were administered 100 g of yogurt-like soybean product for 3 weeks. The plate count method combined with specific PCR and quantitative real-time PCR were used to estimate the numbers of total Bifidobacterium and B. animalis subsp. lactis in fecal samples. B. animalis subsp. lactis was detected during the administration period but not before. The intake number of B. animalis subsp. lactis OPB-1 was 2.4 × 1010 CFU/day by the plate count method and 4.2 × 1013 copies/day by quantitative real-time PCR. However, the number of excreted B. animalis subsp. lactis per day was estimated to be more than 10 times the intake number, by both methods. The percentage of Bifidobacterium increased from 16.9 ± 21.8% to 34.1 ± 20.4% by the plate count method and 18.9 ± 13.4% to 27.8 ± 15.8% by the T-RFLP method after 3 weeks administration.