Effect of probiotics on five biochemical microflora-associated characteristics, in vitro and in vivo

Abstract

Background: Several bacterial strains, mainly those belonging to the genera Lactobacillus, Enterococcus, Streptococcus and Bifidobacterium, are currently used as probiotics. Objective: The aim of this study was to investigate the influence of probiotics on five biochemical microbial-related functions in vitro and in vivo, in gnotobiotic mice, by applying the GAC/MAC (germ-free animal characteristic/microflora-associated characteristic) concept. Design: Sixteen probiotics were monoinoculated in vitro and/or monoassociated to germ-free mice to investigate the following biochemical parameters in large intestinal samples: inactivation of tryptic activity, degradation of β-aspartylglycine and of mucin, conversion of bilirubin to urobilinogen and β-glucuronidase activity. Results: Lactobacillus reuteri 2010, L. rhamnosus strain 271, L. rhamnosus ATCC7469 and L. rhamnosus GG ATCC53103 expressed β-glucuronidase activity. The other parameters tested were not influenced by any of the probiotics. Conclusions: Bacterial β-glucuronidases have an important intestinal function. As many microbial-host and microbe-diet interactions occur in the gastrointestinal tract of mammals, microbial-related functions should be studied in greater detail in probiotics.