title: A new technique to determine hydrogen excreted by gnotobiotic rats.
abstract: A new system, that allowed the monitoring of hydrogen (H2) excretion by gnotobiotic rats without affecting their defined microbial status, was developed. The system consists of an isolator containing a chamber for an experimental animal, and a life-support system (LSS), with a sampling port outside the isolator connected to it. H2 accumulation in the system was measured by analysing a defined volume of gas after removal. H2 concentrations were determined with an electrochemical cell or by gas chromatography. To validate this technique, H2 excretion by germ-free (GF) and mono-associated rats fed a chemically defined diet was measured after oral application of lactulose. Mono-associated rats had been obtained by colonizing GF rats with a H2-producing Clostridium perfringens type A strain isolated from human faeces of a healthy volunteer. Application of 50 mg lactulose to the mono-associated rats resulted in a significant increase in H2 excretion. The net H2 excretion was 7.82+/-1.28 ml H2 in 12 h corresponding to a net maximal rate of 1.1+/-0.3 ml H2/h. In contrast, in experiments with GF rats, less than 0.13 ml H2 were detectable within 12 h. The technique presented is a useful tool for studying bacterial H2 metabolism in vivo under gnotobiotic conditions.
authors.affiliation: Department of Gastrointestinal Microbiology, German Institute of Human Nutrition, Potsdam-Rehbricke.
authors.forename: L
authors.initials: L
authors.lastname: Hartmann
authors.forename: D
authors.initials: D
authors.lastname: Taras
authors.forename: B
authors.initials: B
authors.lastname: Kamlage
authors.forename: M
authors.initials: M
authors.lastname: Blaut
mesh_terms: D000818:Animals; D003016:Clostridium perfringens / Q000378:metabolism; D003106:Colon / Q000382:microbiology; D015169:Colony Count, Microbial; D003903:Deuterium / Q000032:analysis; D005243:Feces / Q000382:microbiology; D005285:Fermentation; D005856:Germ-Free Life; D006859:Hydrogen / Q000032:analysis / Q000378:metabolism*; D007700:Kinetics; D051381:Rats; D011919:Rats, Inbred Strains; D017208:Rats, Wistar
chemical_list: D006859:Hydrogen; D003903:Deuterium