The Effect Of High-fat Diet And Oat Beta-glucan On Physiology And Gut Microbiota In Human Flora-associated Mice

The importance of intestinal flora to human health is increasingly being valued. It hasbeen found there is a necessary connection between the gut microbiota and obesity. How toregulate intestinal flora to protect the host health through diet has become a hot scientificresearch problem. Oat beta-glucan is able to lower blood total cholesterol, to improve bloodlipid profiles, to attenuate blood glycemic as well as to maintain body weight, to promoteintestinal bacteria growth and antibacterial effect. Human Flora-Associated (HFA) animalmodel partly simulate the characteristics of the human intestinal flora, Thus it was used tostudy the effect of diet on human intestinal flora. In this study, to explore the relationshipbetween obesity, diet and gut flora, and to provide an important theoretical basis to promote ahealthy diet way, obese animal model was build by using HFA mice fed a high-fat diet, and atthe same time supplements with5%oat beta-glucan were administrated to study the effect ofhigh-fat-diet and oat beta-glucan on physiology and gut microbiota in human flora-associatedmice by determining body weight, blood glucose and blood lipid levels, staining the livertissue and adipose tissue and using PCR-DGGE method to analyze changes of gut microbiotastructure and microbial diversity in HFA mice.The main results are as follows:(1) High-fat diet significantly increased body weight, adipose index (P<0.05) in HFAmice, and obese HFA mouse model was successfully established. While Oat beta-glucan cansignificantly inhibited the gain of body weight (P<0.05) and the increasing of adipose index(P <0.05) in high-fat diet-fed HFA mice.(2) High-fat diet significantly increased fasting glucose concentration and impairedfasting glucose tolerance in HFA mice, while oat beta-glucan had significant hypoglycemiceffect (P <0.05), significantly improved fasting glucose tolerance in HFA mice fed a high-fatdiet (P <0.05). Furthermore, High-fat diet significantly increased the concentration of serumtotal triglyceride and cholesterol (P<0.05), while oat beta-glucan significantly inhibited theincreasing in total serum triglyceride levels (P<0.01), but there was no significant effect onserum total cholesterol in high-fat diet-fed HFA mice.(3) High-fat diet damaged liver tissue structure and lead to hepatic steatosis in HFA mice, while oat beta-glucan inhibited hepatic steatosis and alleviated liver tissue structural damagein high-fat diet-fed HFA mice; High-fat diet obviously caused hypertrophy of lipocyte, whileoat beta-glucan significantly alleviated the hypertrophy of lipocyte in high-fat diet-fed HFAmice.(4) Both oat beta-glucan administration and high-fat-diet feeding led to significantchanges in gut microbiota structure in HFA mice, while normal diet allowed intestinalmicrobial community structure in HFA mice to maintain the intestinal flora relatively stable ina longe period of time. Although high-fat-diet had no significant effect on the microbialdiversity of gut microbiota in HFA mice, but high-fat-diet promoted the overgrowth ofStaphylococcus lentus, Staphylococcus cohnii subsp., Clostridium glycolicum in the gut ofHFA mice. Furthermore, Oat beta-glucan significantly reduced the microbial diversity of gutmicrobiota in HFA mice (P<0.05); High-fat-diet reduced microbial diversity of the genusLactobacillus and Bacteroides(P<0.05) in the gut of HFA mice, while oat beta-glucansignificantly increased microbial diversity of the genus Lactobacillus(P<0.05)andBacteroides(P<0.01) in gut of high-fat diet-fed HFA mice.