Effects Of Different Dietary Fats On Gut Microbiota

Meat is rich in protein,fat,minerals,vitamins and other nutrients,and played an important role in the process of human evolution and development.Along with the improvement of living standard,consumers have increasingly been awared of the relationship between diet and health.Fat plays an important role in human health.In recent years,the health of the middle-aged people has been paid much attention.However,it is much less studied about the mechanism of the fat on middle-aged adults.In addition,the relationship between gut microbiota and high-fat diet has been taken much attention,but it is still unclear how gut microbiota in middle-aged populations responds to dietary fats at a normal dose.In this study,we explore the responses of caecal microbiota to fermentation of lard,fish oil and soybean oil in a vitro study.And then,we used middle aged rats to profile caecal microbiota and colonic microbiota after ingestion of fats derived from soybean oil,lard and fish oil.On this basis,the mRNA levels of biomarkers for inflammation in the colon were detected to reflect the inflammatory response from gut bacteria to the host.The results are expected to be helpful for health maintenance via dietary regulation.1.in vitro fermentation characteristics of different dietary fatWe study in vitro fermentation characteristics of different dietary fats.Gastrointestinal digestion of three dietary fats was simulated in which fat was emulsified with bile salts and hydrolyzed by pancreatic lipase treatment,then added into culture medium for caecum bacteria fermentation at 37? and anaerobic condition for 24 h.We collected the fermentation liquid,and detected the composition of gut bacteria and SCFAs level.The results showed that the composition of gut bacteria and SCFAs level in three fat fermentation liquids were significantly different.Fish oil group differed from the lard group and the soybean oil group.The fish oil group had the highest abundances of Proteobacteria and D.esulfovibrio,but the lowest Prevotella.The predictive functions of the microbiota genes showed that fish oil induced higher abundances of predicted lipid metabolism and bile acids metabolism,but lower abundances of predicted amino acid metabolism and amino acid related enzymes.The concentrations of acetic and total SCFAs in fermentation liquids were substantially lower in the lard group.The results also showed that the changes of the structure and the fermentation ability of gut bacteria were indeed caused by dietary fat source,but in vitro could not completely simulate the in vivo condition.The mechanism of effect of different dietary fats on gut bacterial community needs based on in vivo.2.Effect of dietary fats on gut microbiota in middle-aged ratsAnimal diets were prepared according to the recommendation of the American Institute of Nutrition(AIN-93M)to meet the nutritional requirements for adult rats.The feces on 0 day were collected to detect the structure of the microbiota.Caecal and colonic contents were collected after 3-month feeding to explore the responses of gut microbiota in middle-aged rats to intake of lard,fish oil and soybean oil.The mRNA levels of biomarkers for inflammation IL-1?,IL-6,IL-17,IL-18 and TNF-a in the colon were detected to reflect the inflammatory response from gut bacteria to the host.The results showed that there were significant differences in composition of gut bacteria among the three diet groups.CYP7A1,a critical enzyme in the formation of bile acids,mRNA level in the liver was the highest in the fish oil group,which led to higher abundances of total bile acids and taurine-conjugated bile acids in fish oil group.In addition,the fish oil group had higher abundances of Desulfovibrionaceae and Bilophila.Quantitative RT-PCR revealed that the fish oil group exhibited higher levels of IL-1?,IL-6,IL-17,IL-18 and TNF-a in colon tissue.A higher abundance of Akkermansia was observed in the lard group(10%kcal fat in diet)as compared to the soybean oil group and the fish oil group.