| Objective:Inulin is an oligofructose.It could be used as a human prebiotic to regulate intestinal flora,thereby regulating blood glucose,reducing the risk of gastrointestinal diseases and enhancing the body’s immunity.Although there were many types of inulin in the markets,different degrees of polymerization of inulin had different effects on intestinal microbes.This study aimed to observe the effects of low degree of polymerization(DP=4.17)and high degree of polymerization(DP=14.5)of inulin on the struction of healthy intestinal microbial community through human and animal intervention experiments.Methods:1.healthy human intervention experiments.: We chose twenty-six healthy volunteers(aged 20-50 years),male or female,and excluding who had gastrointestinal diseases or taking antibiotics and other drugs recently.Then finally selected twenty people for this experiment.Follow the principle of the ratio of 1:1 and random control,there were divided into one group with high degree polymerization of inulin and another group with low degree polymerization of inulin.Feces were collected before and after ingestion of inulin,total DNA was extracted and the 16Sr-RNA gene V3-V4 hypervariable region was sequenced by using the Illumina-Mi Seq high-throughput sequencing platform.Then analyzed the diversity of Alpha diversity,beta diversity and microbial community composition.2.Mice intervention experiments:Twenty C57/BL mice aged 6-8 weeks were selected,male and female,weighing 18-22 g.Follow the principle of the ratio of 1:1 and random control,it was divided into one group with high degree polymerization of inulin and another group with low degree polymerization of inulin.Feces were collected before and after ingestion of inulin and total DNA was extracted.The follow-up experiment was consistent with the intervention experiment of healthy people.Results: 1.From the Alpha diversity index,there was no significant change in the Alpha diversity index between high-polymeric inulin and low-polymeric inulin in the healthy human intervention experiments.In mice intervention experiments,the Chao1 index,ACE index and Shannon index decreased(P<0.05)under the influence of low degree of polymerization of inulin;the Alpha diversity index of high degree of polymerization of inulin did not change significantly.2.PCA analysis indicates that inulin had a significant effect on the structure of the intestinal flora.Specifically,the structure of the intestinal flora was very close when healthy people taking different degrees of polymerization of inulin before.After taking inulin with different degrees of polymerization,the intestinal flora was located in different quadrants.In the species composition of intestinal microflora of mice,there was no significant difference in the intake of different degree of polymerization of inulin.3.The dominant intestinal flora of healthy people,such as Bifidobacterium and Lactobacillus,did not change significantly before and after the intervention of inulin.Intestinal core microbiota,such as Bacteroides、Parabacteroides,also did not change significantly before and after the intervention of inulin.Bacteroides,Lactobacillus and other mouse intestinal flora had no significant changes before and after the intervention of inulin.Bacteroides,Parabacteroides and other intestinal core microbiota also did not change significantly before and after the intervention of inulin.4.In the healthy people intervention experiment,there was no significant abundance change in the KEGG functional spectrum analysis,such as Metabolism、Genetic Information Processing and so on between high-polymeric inulin and low-polymeric inulin.Before and after taking the inulin,PICRUSt predicted that level 2 KEGG groups changed.Specifically,when mice fed with high-polymerity inulin during the mouse intervention experiment,the relative abundance of Cell growth and death increased;when mice fed with low-polymerity inulin during the mouse intervention experiment,the relative abundance of Lipid metabolism was increased;when mice fed with high-polymerity inulin during the mouse intervention experiment,the relative abundance of Biosynthesis of other secondary metabolites and Amino acid metabolism was reduced.5.From the difference in species abundance,it was found that at the level of the gate,after the intervention of high-polymeric inulin,the common change of the intestinal flora between the healthy population and the mice was that Proteobacteria had an increasing trend in the total community.After the intervention of low-polymerity inulin,the common change of intestinal flora in healthy people and mice was that the abundance of Bacteroidetes increased and the abundance of Proteobacteria decreased.Conclusions: In mouse intervention experiments,different degrees of polymerization of inulin had different effects on the structure of intestinal flora.The low degree of polymerization of inulin had a more obvious effect on the structure of intestinal flora.2.In the mouse intervention experiment,the level 2 KEGG groups changed.Changes in the function of these genes suggested that the addition of inulin could improve the composition of the bacterial flora and increase the probiotic effect. |
