The Anti-obesity Effect And Mechanism Of Eurotium Cristatum On Dogs

As a disease,obesity is caused by abnormal body energy metabolism,which leads an excessive fat accumulation.Obesity can induce diabetes,cardiovascular disease,bone and joint disease,cancer,and even death.At present,there are about 1.9billion obese adults in the world,and about 50% of pet dogs and cats are obese.It is very necessary and urgent to adopt appropriate methods to prevent obesity.Studies showed that obesity is closely related to the disorders of gut microbiota.The high fat diet could induce the abnormal growth of some microorganisms in the intestine,especially some gram-negative pathogenic bacteria which could greatly increase.The lipopolysaccharide(LPS)was produced by gram-negative pathogenic bacteria which could combine with chylomicrons and through the intestine to enter the circulatory system.The circulation of low-concentration of LPS could induce systemic chronic inflammation,and the inflammatory factors will induce abnormal glucose and lipid metabolism.Researches showed that food,probiotics and prebiotics could reduce body weight and fat accumulation by improving gut dysbiosis.As a fermented tea,fuzhuan tea has a good effect on reducing body weight.Eurotium cristatum(E.cristatum)is the dominant bacteria in the production process of Fuzhuan tea,and it is also the main strain that forms the unique quality and flavor of Fuzhuan tea.However,the current researches on E.cristatum mainly focus on the identification and physiological characteristics of strains.The research on the effects of E.cristatum on disease is still blank.Therefore,In this study,we aimed to investigate the probability E.cristatum may reduce diet-induced obesity by regulating gut microbiota on obese mice and dogs,and then explore the effects of polysaccharides isolated from E.cristatum on obesity and gut microbiota.Firstly,8-week-old male C57BL/6J mice were fed with an standard diet or high fat diet.The mice of the experimental group were gavaged with E.cristatum,and the mice of the control group were given equal volume saline.The experiment was lasted for 8 weeks,the body weight was weighed every week.After the glucose tolerance trial,the mice were sacrificed and the samples were collected for subsequent analysis.The results show that E.cristatum could significantly reduce the body weight gain and fat accumulation,and significantly improve liver fat infiltration,reduce the expression of sterol regulatory element binding proteins(SREBP-1c),fatty acid synthase(FAS)in the liver,serum triglycerides(TG),total cholesterol(TC),and low-density lipoprotein cholesterol(LDL-C)in obese mice.Glucose tolerance trial results show that E.cristatum could significantly reduce the fasting blood glucose,fasting insulin and insulin resistance index and accelerate the elimination of glucose in obese mice.In addition,results showed that E.cristatum significantly decreased the serum LPS concentration and interleukin(IL-1?)and tumor necrosis factor-?(TNF-?)of obese mice.The 16S rRNA sequencing results showed that E.cristatum could significantly improve the diversity and composition of gut microbiota in obese mice.Besides,at different taxonomic levels,E.cristatum significantly changed the abundance of specific bacteria.In order to investigate relationship between the anti-obesity effect of E.cristatum and the changes of gut microbiota,we conducted fecal microbiota transplantation(FMT)experiment.The FMT result showed that E.cristatum reduced body weight by improving the gut dysbiosis of obese mice.Furthermore,in order to determine the effective ingredients in E.cristatum on reducing body weight.We preliminarily determined that polysaccharides are the main components of E.cristatum on weight loss effects.Therefore,C57BL/6J mice were fed with high fat diet or standard diet.The mice of experimental group were gavaged with polysaccharide,and the mice of control group were gavaged with an equal volume of saline,the body weight were weighed once a week.The glucose tolerance test was performed one day before the end of the experiment.After the experiment,the mice were sacrificed and samples were collected for subsequent analysis.The results show that E.cristatum polysaccharides could significantly reduce the weight gain and fat accumulation,and significantly reduce liver fat infiltration,improve liver lipid metabolism and blood lipid levels,maintain glucose metabolism homeostasis,and reduce serum LPS concetration and the inflammatory of obese mice.In addition,the 16S rRNA sequencing results showed that E.cristatum polysaccharides significantly changed the diversity and composition of gut microbes in obese mice.At the same time,the abundance of specific bacterial species were changed.In order to determine the relationship between the weight loss effect of E.cristatum polysaccharide and the change of gut microbiota,we conducted a FMT trial.The results showed that E.cristatum polysaccharide played its anti-obesity effect by mediating the change of gut microbiota.The above experimental results show that E.cristatum polysaccharides and E.cristatum played their anti-obesity effect by improve gut dysbiosis.In order to investigate the anti-obesity effect of E.cristatum on obesity in pet dogs and cats,2-year-old male beagle dogs were fed with high fat diet or standard diet.The whole animal experiment is classified into two-phase.In phase 1,five 2 years old beagle dogs were fed with standard diet and ten dogs were fed with high fat diet for 5 months.In phase 2,the dogs of control group were fed with standard diet or high fat diet,while the obese dogs were fed with high fat diet mixed with E.cristatum.After 8 weeks,blood was collected for biochemical analysis and glucose tolerance trial was performed.The results showed that compared with the beagle dogs of standard diet-fed group,high fat diet-fed significantly increased the body weight of beagle dog.The biochemical results showed that the abnormity of alanine aminotransferase(ALT),aspartate aminotransferase(AST),?-glutamyltransferase(GGT),TG and cholesterol(Chol)in obese beagle dogs,while E.cristatum improved these situations.The glucose tolerance trial results showed that the glucose metabolism levels of all beagle dogs were normal and maintained within the normal range.The 16S rRNA sequencing results showed that compared with healthy dogs,the gut microbial composition and diversity of obese dogs have changed.E.cristatum alleviateed diversity and composition of the gut microbiota in obese beagle dogs.In summary,our results showed E.cristatum and its polysaccharides played their anti-obesity effects by improving gut dysbiosis.The experiment of beagle dog indicated that E.cristatum could reduce body weight gain and improve lipid metabolism of obese dogs.Therefore,our experimental results show that E.cristatum and its polysaccharides are potential probiotics and prebiotics that can be used for obesity prevention and treatment,and their anti-obesity effects are associated with the improve of gut dysbiosis.