Inulin-type fructans stimulated the growth of exogenously administered Lactobacillus plantarum No. 14 in the mouse gastrointestinal tract.

This study examined the effects of the inulin-type fructans known as fructo-oligosaccharide (FOS) and inulin on the growth and persistence of Lactobacillus plantarum No. 14 (LP14) in the gut. Cultivation in medium that contained either FOS or inulin revealed that both fructans supported the growth of LP14. Fecal recovery of viable L. plantarum at 24 and 30 h following administration of LP14 were highest in mice fed inulin, followed by mice fed FOS and the control diet. However, neither of the fructans prolonged the appearance of LP14 in the gut. Cultivation in fecal extract medium prepared from mice fed each of the test diets showed higher growth of LP14 in the mice fed fructans. Histological analysis following fluorescein-stained LP14 administration showed that LP14 was largely localized to the luminal contents. These results suggest that inulin-type fructans support the growth of LP14 in the luminal contents only during their passage through the gut.