ADAPTATION OF RATE OF ORGANIC-ACID PRODUCTION OF HINDGUT BACTERIA TO CHRONIC INTAKE OF GALACTOOLIGOSACCHARIDE IN THE RAT

We studied the adaptational effect of galactooligosaccharide (GOS) on the concentration of organic acids in cecal content, fecal water conte nt and organic acid production from GOS in cultures with the cecal ino cula of rats fed GOS for 1, 2, 7 or 21 d. The fecal water content of r ats fed GOS for 1 d was higher than that of the controls. The concentr ation of each organic acid in the cecal contents was affected by diet, not by the time of adaptation. In in vitro fermentation, lactic acid was produced rapidly and remained in the cultures with homogenates of rats fed GOS for id. Acetic acid in the cultures of the GOS-diet rats' cecal homogenates was produced more rapidly than that of the controls on days 2, 7 and 21 of adaptation. Propionic acid was produced more r apidly in the GOS homogenate cultures than in that of the controls on day 2. Butyric acid in the cultures from the GOS-fed rats was produced more rapidly than that of the controls on days 2 and 21. These result s suggest that the time period of GOS feeding influenced the productio n rate of each organic acid, and the changes varied among acids.