The modulation effect of lotus (Nelumbo nucifera Gaertn.) seeds oligosaccharides with different structures on intestinal flora and action mode of growth effects on Bifidobacterium in vivo and in vitro

Natural lotus seed oligosaccharides monomers (LOSs: LOS3-1, LOS3-2, and LOS4) were prepared by preparative chromatography and were hydroxyl-labeled with fluorescein isothiocyanate (FITC). The prebiotic properties of LOSs by the gut microbiota of male Balb/C mice in vivo and in vitro were studied. In vivo experiment results showed that LOS4 could significantly increase the average daily food consumption, weight, liver index and the abundance of Bacteroides and Bifidobacterium for mice (p < 0.05). In addition, LOS4 also had significant proliferation effect on Bifidobacterium adolescentis and longum in vitro (p < 0.05). Laser confocal microscopy observation showed interaction site between LOS4-FITC and Bifidobacterium adolescentis was located outside and inside of cell, which was completed within 1 h. The relationship between structures of LOSs and prebiotics of intestinal flora (especially Bifidobacterium), and expanded the knowledge on the effects of carbohydrate polymerization degree (DP) and glycosidic bond connection with fermentation selectivity of bacteria was studied.