In vitro evaluation of gastrointestinal survival of Lactobacillus amylovorus DSM 16698 alone and combined with galactooligosaccharides, milk and/or Bifidobacterium animalis subsp lactis Bb-12

Probiotic properties of Lactobacillus amylovorus DSM 16698 were previously demonstrated in piglets. Here, its potential as a human probiotic was studied in vitro, using the TIM-1 system, which is fully validated to simulate the human upper gastrointestinal tract. To evaluate the effect of the food matrix composition on the survival of L amylovorus DSM 16698 in TIM-1, the microorganism was inoculated alone or with prebiotic galactooligosaccharides (GOS), partially skimmed milk (PSM) and/or commercial probiotic Bifidobacterium animalis subsp. lactis Bb-12 (Bb-12). Samples were collected from TIM-1 for six hours, at one-hour intervals and L amylovorus populations were enumerated on MRS agar plates with confirmation of identity of selected isolates by randomly amplified polymorphic DNA (RAPD) fingerprinting. The cumulative survival for L amylovorus alone (control) was 30% at the end of the experiment (t = 6 h). Co-administration of L amylovorus with GOS. PSM and/or Bb-12 increased its survival in comparison with the control significantly from the 4th hour after ingestion onwards (P<0.05). Furthermore, by the use of High Performance Anion Exchange Chromatography, both L amylovorus and Bb-12 were observed to promptly degrade GOS compounds in samples collected from TIM-1, as assessed at t = 2 h. Hence, food matrix composition interfered with survival and growth of L. amylovorus during passage through TIM-1, providing leads towards optimization of probiotic properties in vivo. (C) 2011 Elsevier B.V. All rights reserved.