excretion in gnotobiotic rats monoassociated with C. butyricum DSM10702 (Cb rats). The rats (n = 12) were administered intragastrically with the solution to be tested and they were placed in respiratory chambers. Air samples taken from the chambers were analyzed for H2 concentration using GC. Treatments successively applied to all rats (for more details, see Material and Methods section and Fig. 5) are boxed. Cross bars indicate standard error of the mean. MW, metabolic weight; *, indicates that P values (Student-Newman-Keuls test) of the differences with the group receiving soy milk is P < 0.01.