Arabinoxylan And Its Complex Polysaccharides Improve Lipid Metabolism Disorder Induced By High-Fat Diet In Mice And Its Mediation Mechanism

As one of the main non-starch polysaccharides(NSP)in cereals,arabinoxylan(AX)has various physiological functions such as blood lipid lowering,antitumor,immune regulation and antioxidant.The possibility of consuming a single NSP in a diversified diet is extremely low,and it is often the case that two or more NSPs are taken together.However,the research on complex polysaccharides using AX as the main raw material is still in its infancy,and its mechanism for lowering blood lipids needs to be improved.In this experiment,AX and its complex polysaccharides were used as the research object.AX was mixed with two different NSPs at a certain ratio and added to the diet of experimental animals to explore the mechanism of different dietary combinations affecting blood lipid metabolism,bile acid metabolism,and gut microbiota.This research has positive significance for the further development of AX as a functional food for the prevention of chronic metabolic diseases,and for the prevention and adjuvant treatment of a series of metabolic imbalances caused by dietary disorders.After 1 week of adaptive feeding,50 male ICR / KM mice were randomly divided into 5 groups,i.e.control group(CON,10% fat energy),high fat diet group(HFD,60%fat energy).8% AX were added to the high fat diet group(HFAX),4% AX and 4%β-glucan were added to the high fat diet group(HFAB),4% AX and 4% xyloglucan were added to the high fat diet group(HFAG).After 8 weeks of feeding on the test diet,mice were sacrificed to collect serum,liver,cecum,colon,small intestine,intestinal digesta and fecal.All samples were stored at-80 ° C for subsequent analysis.The main findings were as follows:1.Compared with CON,the high-fat diet increased the body weight of mice;increased serum TC,TG,LDL-c,liver TG,FAS,and CYP7A1 levels(p<0.05);reduced serum HDL-c and liver ACO levels(p<0.05).The high-fat diet caused liver steatosis,cell necrosis,and inflammation in mice and inhibited liver fatty acid oxidation and energy metabolism.After supplementing three kinds of NSPs to the high-fat diet,liver and serum lipid disorders in high-fat mice were alleviated,but the mechanism and degree of relief were different: After AX supplementation,serum HDL-c levels were increased(p<0.05),and liver TG and CYP7A1 levels were decreased(p<0.05)in high-fat mice;Serum TC,TG,liver TG,FAS,CYP7A1 levels of high-fat mice were decreased(p<0.05)after AB supplementation;After AG supplementation,serum levels of TC,TG,liver TG,and CYP7A1 in high-fat mice were decreased(p<0.05)and liver ACO levels were increased(p<0.05).The liver TC level of the HFAG group was lower than that of the HFAB group(p<0.05).2.The results of bile acid metabolism analysis showed that high-fat diet reduced the expression level of Fxr and small intestine Tgr5 in the liver(p<0.05),increased the expression level of Cyp7a1 in the liver(p<0.05),increased the level of bile acid in the enterohepatic circulation,and caused the disorder of bile acid balance.After adding AX to the high-fat diet,serum bile acid levels were significantly reduced(p<0.05),and the expression level of Cyp7a1 in the liver was decreased(p<0.05).After supplementing of AB,serum and liver bile acid levels were significantly reduced(p<0.05),liver Fxr and its downstream Cyp7a1 expression levels were decreased and increased(p<0.05),respectively.After the addition of AG,bile acid levels were decreased throughout the enterohepatic circulation(liver,intestine,serum),Fxr and Tgr5 levels in the small intestine were increased(p<0.05).The results showed that in the three groups of NSPs,AG had the strongest bile acid-reducing effect,followed by AB,and AX was the weakest.3.The results of gut microbiota analysis showed that the high-fat diet reduced the abundance and diversity of the microbial,caused disturbances in the gut microbiota,increased the level of conditioned pathogens,and reduced the level of beneficial bacterias.Compared with HFD,AX increased the levels of micro-organisms that are beneficial to health,such as Allobaculum,Bifidobacterium and Faecalitalea.In addition to the same beneficial microorganism increase observed in the HFAX group,the levels of Lachnospiraceae＿UCG＿001,Parabacterioides,Bacteroides and Marvinbryantia in the HFAB and HFAG groups also been increased.Moreover,Akkermansia and Bacteroides levels were higher in the HFAG group while Allobaculum and Alistipes levels were higher in the HFAB group.NSP improved the intestinal microecology by changing the abundance of specific probiotic strains,and complex polysaccharides had a better remodeling effect on intestinal microecologies than AX,but the effects of two complex polysaccharides on specific microbial were different.Compared with AB,AG’s stronger proliferation effect on Akkermansia and Bacteroides may make it have better lipid-lowering effect.