Effects of DFA IV in rats: Calcium absorption and metabolism of DFA IV by intestinal microorganisms

Di-n-fructose-2,6':6,2'-dianhydride (DFA IV) is a disaccharide consisting o f two fructose residues that can be prepared from levan by levan fructotran sferase from Arthrobacter nicotinovorans GS-9, and it can be expected to ha ve novel physiological functions from its unique structure. In this study, the effects of DFA IV on calcium absorption and the metabolism of DFA IV by intestinal microorganisms were studied in rats to examine the physiologica l functions of DFA IV. The apparent calcium absorption in rats fed with DFA IV was significantly h igher than that in the control rats, and it seems that calcium absorption h ad almost been completed at the end of the small intestine. DFA IV also inc reased the calcium absorption in in vitro experiments, using everted jejuna l and ileal sacs, and this result supports the finding obtained in the in v ivo experiments. These results indicate that DFA IV may have a function for increasing the calcium absorption in the small intestine of rats. However, the effect in the large intestine could not be clearly observed because of the lack of calcium that reached there. The results of analyses of organic acids in the cecal and colonic contents and of DFA IV in the fecal, cecal, and colonic contents showed that the met abolism of DFA IV by microorganisms in the large intestine progressed gradu ally, and that DFA IV was converted mainly to acetate, butyrate, and lactat e.