The Preventive Effects Of Mannan Oligosaccharide On Obesity And Ulcerative Colitis By Gut Microecology Disturbance

With the development of social economy,dietary structure and living habits of individuals have undergone tremendous changes.Obesity and inflammatory bowel disease have become global health problems,which are caused by high-calorie western pattern diet and unhealthy living habits.Mannose oligosaccharide(MOS)was listed as a new raw food material in China in 2013.It is a new oligosaccharide prebiotic,which mainly is extracted from yeast and Amorphophallus konjac.Mammals cannot digest MOS because of the deletion of ?-1,4 glycosidase,but MOS can be degraded by gut microbiota and possesses antioxidant,anti-inflammatory effects.However,the effect and potential mechanism of MOS on obesity and inflammatory bowel disease are still unclear.With this background,MOS was selected to investigate the protective effect and molecular mechanism of colon health.(1)Three-month-old male ICR mice were divided into three groups: CON group,highdose MOS treatment group(MH,200 mg/kg/day)and low-dose MOS treatment group(ML,100 mg/kg/day).The test group mice were treated with MOS to investigate the effects of MOS on the gut microbiota and gut microbiota metabolites.Results showed that MOS treatment significantly reduced the Shannon index and a significantly separated the cluster of the ?diversity between MOS treatment group and CON group.MOS significantly changed the composition of gut microbiota,increased the abundance probiotics bacteria,such as Lactobacillus,the abundance increasing of Lactobacillus was also detected in 16 S r RNA sequencing data.Furthermore,MOS treatment significantly reduced the abundance of pathogens in the gut of mice,such as Escherichia,Salmonella,Helicobacter.MOS treatment also significantly increased the content of acetate,propionate and butyrate in mice gut.(2)Three-month-old male ICR mice were induced obesity by Western diet(WD)to study the effect of MOS on obesity and intestinal health problems.The results showed that MOS suppressed the weight gain,fatty liver,and hyperlipemia by up-regulating the expression of lipolysis genes Pparg,and inhibiting the expression of lipogenesis genes Ppara.MOS treatment also alleviated WD-induced insulin resistance.Interestingly,MOS reshaped the gut microbiota composition,a significant separation was observed between the MOS treatment group and WD group of ? diversity.The abundance of Bifidobacterium and Lactobacillus were significantly increased after MOS treatment,the level of butyrate was also significantly increased after MOS treatment in gut and serum.In the correlation analysis,the butyrate was negatively correlated with energy intake and NPY expression,the NPY expression was positively correlated with body weight gain,MOS can suppress appetite by increasing the production of short-chain fatty acids.In this section,it is found that MOS treatment can alleviate the increase in body weight,adipocyte hypertrophy,fatty liver and hyperlipemia by promoting lipolysis and inhibiting appetite.(3)Three-month-old male ICR mice were induced ulcerative colitis by dextran sodium sulfate used to investigate the effects of MOS on anti-inflammatory bowel disease.The results showed that MOS treatment significantly inhibited the increase of the disease activity index(DAI)and relieved the ulcerative intestinal damage.MOS treatment effectively reduced the colon weight/length ratio and maintained the integrity of gut mucosa.The ratio of Firmicutes/Bacteroidetes was significantly reduced by MOS treatment,the clustering of the gut microbiota showed significant separation between MOS treatment group and DSS group,MOS altered the gut microbiota composition.Five groups of co-abundance groups(CAGs)were detected by Sparse Correlations for Compositional of the 16 S r DNA sequencing data.MOS treatment significantly increased the abundance of CAG4 and CAG5,and suppressed the abundance of CAG2.Lactobacillus was classified into CAG4.MOS treatment also significantly increased the colon acetate,propionate and butyrate.In the correlation analysis,CAG4 negatively correlated with DAI index,propionate and butyrate positively correlated with DAI index and the ratio of colon weight to length.MOS may alleviate intestinal inflammation by increasing the probiotic and SCFAs levels in colon.In summary,MOS reshape the composition of gut microbiota,increase the abundance of colon probiotics and the level of colon SCFAs,which may suppress obesity and alleviate inflammatory bowel disease.This work explains anti-obesity and anti-inflammatory effects of MOS by reshaping the gut microbiota composition,and also provide a theoretical foundation for development of natural functional food components combating obesity and inflammatory.