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 . ve biochemical microbial-related functions in vitro and in vivo, in gnotobiotic mice, by applying the GAC:MAC (germ-free animal characteristic:micro oraassociated 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 b-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 in uenced 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.