Effect Of Lotus Seed Resistant Starch On Intestinal Functional Improvement And Metabolism In Rats

The intestinal tract is responsible for digesting and absorbing nutrients because of its special tissue structure.At the same time,the mucosal barrier in the intestine is also a defense against the infection of external pathogenic microorganisms.Intestinal flora,on the one hand,mainly use the food residue that the host ingests as the main energy source;on the other hand,it can participate in the energy metabolism of the host through various channels.Intestinal flora can provide certain vitamins and beneficial substances to the host.In addition,it also have the ability to decompose some endogenous toxins.Our previous study found that the structure of intestinal microflora was affected and the richness of bacteria was reduced by the intake of lotus seed resistant starchwhich prepared by autoclave method(GP-LRS3).The intake of GP-LRS3 could also reduced the number of bacteria that have pathogenic capacity,and increased the number of micro-organisms that produce short-chain fatty acids.In order to further study its prebiotic effect,GP-LRS3 was utilized as the research material in this study to investigate the effect of GP-LRS3 on the intestinal functional improvement in rats using metabonomics.Therefore,the effects of GP-LRS3 on the intestinal morphology,intestinal flora and metabolites via the rats fed with resistant starch.The results were as follows:(1)The increase of the body weight of rats was significantly inhibited by GP-LRS3 intakes in the experimental groups and the bioconversion rate of the feed was also reduced(p<0.05).Through the analysis of blood index data of rats,the results showed that rats fed resistant starch could not cause rejection of the body.By analyzing the data of small intestine and large intestine morphology of rats,the results showed that GP-LRS3 could effectively increase the length and width of villus of small intestine in rats,and increase the ratio of villus height and crypt depth,as well as increase the effective absorption area of small intestine.The small intestine crypts became lighter,and the muscular layers of the small intestine,cecum,and colon thicken by the GP-LRS3 intakes,which enhanced the mechanical digestion.Moreover,the thickness of the mucous layer of the small intestine,caecum,and colon increased,which enhanced the defensecapacity against the invasion of exogenous pathogenic bacteria.The results of the imaging observation of the tissue slices by HE staining confirmed the above conclusions.In summary,the mechanical digestion and nutrient absorption of rat small intestine were improved and the defense capacity against the pathogenic bacteria was enhanced by the GP-LRS3 intakes.(2)According to the principal component analysis of qPCR-DGGE data,the structure of intestinal flora in rats was regulated by the intake of GP-LRS3.It could increase the abundance of acetic acid,propionic acid and butyric acid bacteria in the intestine of rats,indicating that GP-LRS3 could effectively promote the proliferation of probiotics in the intestine.The intake of GP-LRS3 reduced the number of pathogenic or potentially pathogenic microflora in the intestine,such as Pseudomonas,Clostridium,and Rhizoctonia,and increased the number of beneficial bacteria,such as Vibrio butyricum,Bacteroides,Rumenococcusbromii and Lactobacilli,which consequently modulate the structure of the intestinal flora in rats.High-throughput sequencing experiment results showed that the abundance of Lactobacillusgenus and Ruminococcusgenus was increased by the intake of GP-LRS3.Furthermore,the functional predictions showed that the carbohydrate-degrading microorganisms accounted for the majority proportion of the intestinal mircobiota and the microbiota in GP-LRS3 group was higher than those ofblank group(named as BK group),which was consistent with the DGGE experimental results.(3)Rat feces collected at different times were used as research objects.Metabolomics was used to study the effect of GP-LRS3 on metabolites in rats.The results showed that there was a significant difference in fecal metabolite profile between the BK group and the GP-LRS3 group.The OPLS-DA map showed that the two groups were well-differentiated,and the obtained biomarkers exhibited dynamic changes in metabolic levels over time as a result of GP-LRS3 intervention.After screening,the differential metabolites were mainly primary bile acids,secondary bile acids and their salts,such as glycocholic acid,bile acid deoxycholic acid,glycochenodeoxycholic acid,and glycosaminodeoxycholic acid sulfate.GP-LRS3 could promote primary bile acid excretion in the intestine of rats,reduce the conversion of primary bile acids to secondary bile acids,and increase the turnover rate of bile acids.This process may be related to the intestinal characteristics bacteria regulated by the intake of resistant starch in rats.