Urinary profiles of volatile and acid metabolites in germfree and conventional rats

Qualitative and quantitative differences in the urinary excretion of volatile and acidic metabolites in germfree and conventional rats were examined by capillary gas chromatography and gas chromatography/mass spectrometry. A number of carbonyl compounds, including several short-chain aliphatic ketones and acetophenone, were higher in the conventional urines, while many heterocyclic compounds (furan derivatives, benzothiazole and others) were lower. Both qualitative and quantitative differences were observed in the urinary excretion of acidic metabolites. Three meta-hydroxy phenolic acids appeared only in the conventional rat urines, while levels of many other aromatic and aliphatic acids were also higher.