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 Bi dobacterium, are currently used as probiotics. Objective: The aim of this study was to investigate the in uence of probiotics on ve biochemical microbial-related functions in vitro and in vivo, in gnotobiotic mice, by applying the G AC:M AC (germ-free animal characteristic:micro ora-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 b-aspartylglycine and of mucin, conversion of bilirubin to urobilinogen and b-glucuronidase activity. Results: Lactobacillus reuteri 2010, L. rhamnosus strain 271, L. rhamnosus ATCC7469 and L. rhamnosus G G ATCC53103 expressed b-glucuronidase activity. The other parameters tested were not in uenced by any of the probiotics. Conclusions: Bacterial b-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.

Biochemical Intestinal Parameters in Germ‐free Minipigs and Rats and in Ex‐germ‐free Minipigs and Rats Monoassociated with Escherichia coli

“…Except for a slight increase in the amount of acetic acid in rats, monoassociation of minipigs and rats with E. coli exerts no influence upon these parameters. This is in agreement with recent studies on association of mice with probiotic strains (Cardona et al., 2002).…”

β-Glucuronidase activity in germ-free, monoassociated and conventional mice

“…After 7 days of colonization, the activity increased slowly, especially in caecum, indicating a delayed establishment of this function. Previous in vitro studies have reported a low b-glucuronidase activity in lactobacilli (4,14). The highest activity has always been reported in some E. coli strains; however, the E .…”

“…Two reasons may explain that: first, the methods used to test b-glucuronidase activity were slightly different from each other and second, the colonization period for the monoassociation in the present study was much shorter (3 and 7 days) than that of the previous study (60 days). Since the EC X7 strain was highly positive in a qualitative test (14), it may also be a theoretical possibility that the strain behaves differently in vitro and in vivo. Enzyme activity approaching that of the Conv group was found in the mice that were conventionalized for longer, i.e.…”

Composition of the early intestinal microbiota

“…The comparison of MACs has been a major component of studies investigating the contribution of the microbiome in, for example, coeliacs relative to controls, 10,18 probiotic or antibiotic treated infants/children compared with controls 11,19 and even to identify changes in gut microbiota-related functionality due to allergic disease. 12,20 While MACs are useful as a tool for screening large populations, such as in epidemiological studies, they are most useful when supplemented with detailed insights into gut microbial composition.…”