The growth of
DFA III-assimilating bacteria in the intestines of rats fed 3%
DFA III for 2 weeks was examined. Sixty-four percent of the
DFA III intake had been assimilated on day 3 of ingestion, and almost all of the
DFA III was assimilated at the end of the experiment. The
DFA III-assimilating bacterium, Ruminococcus productus, in
DFA III-fed rats was in the stationary state of 10(8)-10(9) cells/g dry feces within a week from 10(6) cells/g dry feces on day 1 of
DFA III ingestion. The number of R. productus cells was associated with the amount of
DFA III excreted in the feces. The
acetic acid produced from
DFA III by R. productus lowered the cecal pH to 5.8. In control-fed rats and
DFA III-fed rats, 94% of secondary
bile acids and 94% of primary
bile acids, respectively, were accounted for in the total
bile acids analyzed.
DFA III ingestion increased the ratio of primary
bile acids and changed the composition of fecal
bile acids. In conclusion, R. productus assimilated
DFA III, produced
short chain fatty acids, and the cecal pH was lowered. The acidification of rat intestine perhaps inhibited secondary
bile acid formation and decreased the ratio of secondary
bile acids. Therefore, it is expected that
DFA III may prevent
colorectal cancer and be a new
prebiotic candidate.