Effects Of Oligosaccharide And Its Combination On Intestinal Microorganisms And Immunomodulation In Mice

Non-digestive oligosaccharides are food ingredients that improve host health by selectively stimulating the growth and activity of intestinal probiotics.In order to investigate the proliferation effect of non-digestive oligosaccharide and its combination on intestinal probiotics,the in vitro proliferation test of non-digestive oligosaccharide against probiotics was carried out,and the animal experiment was carried out in mice.The intestinal flora of mice was analyzed by high-throughput sequencing technique and the immune indexes of mice were determined.The results were as follows:1.Non-digestive oligosaccharides and different combinations with good proliferation effect on probiotics in vitro were screened.One oligosaccharide was added to the skim milk culture medium: oligosaccharide,fructose,xylose oligosaccharide,and three oligosaccharides were combined: galactose oligosaccharide and fructose oligosaccharide,galactose oligosaccharide and xylose oligosaccharide.Different ratios of fructose-oligosaccharides to xylose oligosaccharides and each combination: 1:1,1:1.5,1.5:1,1:2,2:1.Then the lactic acid content and the number of live bacteria in fermented milk were determined by inoculation and fermentation.The optimal addition of non-digestive oligosaccharides and different combinations was0.5% galactose oligosaccharide and xylose oligosaccharide.1% with fructose oligosaccharides;Xylooligosaccharides and galactose oligosaccharides(1:1.5)0.5%,oligosaccharides and fructose oligosaccharides(2:1)0.5%,xylooligosaccharides and fructose oligosaccharides(2:1)0.5%,Xylose oligosaccharides and galactose oligosaccharides(1:1.5)0.5% had the best value-added effect.2.The effects of fructose oligosaccharides,xylose oligosaccharides and galactose oligosaccharides on intestinal flora in mice were studied.The mice were randomly divided into 7 groups: blank control group,xylose oligosaccharide group and galactose oligosaccharide group.O-galactose group,xylo-oligosaccharides and galactose oligosaccharides(1:1.5)group,xylo-oligosaccharides and fructose-oligosaccharides(2:1)group,galactose-oligosaccharides / fructose oligosaccharides(2:1)group,were given orally for 20 days.Fresh feces of mice were collected and the changes of microbial community composition and structure were analyzed by high-throughput sequencing technique.The results showed that the intestinal tract of the experimentalgroup was higher than that of the control group.The ratio of beneficial bacteria and pathogenic bacteria was significantly different.The diversity and richness of intestinal flora were the highest in the composite oligosaccharide group,followed by the single oligosaccharide group.At the genus level,compared with the control group,the experiment group increased the species abundance of beneficial bacteria significantly(P < 0.05),and the combination group of xylo-oligosaccharide and galactose(1:1.5)increased the species abundance of beneficial bacteria significantly(P<0.05).Xylooligosaccharides and fructose oligosaccharides(2:1)significantly increased the species abundance of Lactobacillus and Bifidobacterium(P<0.05).3.The immunomodulatory effects of fructose oligosaccharides,xylose oligosaccharides and galactose oligosaccharides on mice were studied.The immune organ index,phagocytosis ability of macrophages and serum hemolysin level were measured.The immunomodulatory effects of different non-digestive oligosaccharides and their combinations on the immune regulation of mice were evaluated by DTH delayed type hypersensitivity and splenic lymphocyte proliferation.Non-digestive oligosaccharides could improve the non-specific immune ability of mice.The immune effect of Xylooligosaccharides and galactose oligosaccharides group was significantly higher than that of the control group(P < 0.01).