The Study Of Fecal Microbiota Transplantation To Promote Intestinal Barrier Function With Post-Injury Recovery By High Fat Diet In Mice

To explore the damage caused by high-fat feed intake to the structure and function of animal intestinal barrier and the role of fecal microbiota transplantation on damaged intestinal barrier repair,it provides a theoretical basis and basic data for animal health breeding under the background of "no resistance" in the world.This study is modeled on 8-week-old clean-grade female KM mice,and the trial is divided into two parts: the first part of the trial is to make a model of intestinal damage,which study the damage of dietary fat levels to the intestinal barrier.60 mice are selected and randomly divided into 3 groups,of which 20 are each in the normal feeding group(ND group),the high-fat feeding group(HD group),and the hunger feeding group(LD group).HD group adopted high-fat feed,mice in the ND group and LD group eat ordinary feed,HD group mice and ND group mice eat freely(about 6 g/d/only),and the LD group mice are fed 60% ND group(3.6g/d/only),and the feeding period is 6weeks,of which the first 2 weeks are prefeed and the last 4 weeks are positive feeding period.The second part of the trial is for the repair of intestinal barrier damage,and the effect of fecal microbiota transplantation and transformed diet on the repair of the damaged intestinal barrier is studied.40 mice are selected,randomly divided into two groups,each group of 20,divided into fecal microbiota transplantation group(FMT group)and transformation diet group(HDN group),the transplanted fecal bacteria are fecal bacteria of mice fed with conventional diets,mice feeding period is 8 weeks,of which the first 2 weeks are the prefeedation period,and the last 6 weeks are the positive feeding period(3-6 weeks each group is fed high-fat feed,7-8 weeks FMT group is fed high-fat feed and fecal microbiota transplantation,HDN group fed conventional feed),feeding standards as the first part.After the trial,6 mice are weighed and randomly selected for dissection in each group to observe the morphological changes of small intestinal tissue and to determine the expression of jejunal microbial diversity and functional genes in changes in the intestinal barrier.The results show that:1)High-fat feed intake will significantly increase mice body weight,fecal microbiota transplantation and feeding high-fat feed would limit the weight gain of mice.The weight gain in the HD group was significantly higher than that in the normal feeding group(P<0.01),and the weight gain in hunger feeding was significantly lower than that in the normal feeding group(P<0.01);fecal microbiota transplantation and diet change could significantly increase the bodyweight of mice,but the difference between the weight gain groups was not significant.2)High-fat feed intake caused damage to the morphology of intestinal tissue in mice,and the villi of each section of the small intestine became significantly shorter(P<0.01),the depth of the jejunal crypt increased significantly(P<0.01),and the ratio of the jejunum and the ileal villi length/crypt depth was significantly reduced(P<0.01);while starvation benefited the intestinal tissue morphology of mice,the height of jejunal and ileal villi increased significantly(P<0.01),and the ratio of duodenal and ileal villi height/depth of the crypt increased significantly(P<0.01).Fecal microbiota transplantation and diet modification could improve the morphology of damaged intestinal tissue,and fecal microbiota transplantation could significantly increase the length of each segment of the injured small intestine villi(P<0.01),and the ratio of jejunal and ileal villi height/crypt depth significantly increase(P<0.01);dietary change could significantly increase the length of damaged duodenal and jejunal villi(P<0.01),and the ratio of jejunal and ileal villi length/crypt depth(P<0.05).3)High fat intake and hunger would significantly reduce the abundance of Bacteroidota and the abundance of Firmicutes in the jejunum(P<0.05),the abundance of Lachnospiraceae and Bacteroidaceae in the HD group increased significantly at the family level;the abundance of Prevotellaceae was significantly reduced(P<0.01),the abundance of Lactobacillaceae and Muribaculaceae in the LD group was significantly increased(P<0.05),the abundance of Prevotellaceae and Lachnospiraceae decreased significantly(P<0.05).Fecal microbiota transplantation and dietary changes both resulted in a significant increase in the abundance of Bacteroidota and a significant decrease in the abundance of Firmicutes in the jejunum(P<0.05);a significant increase in the abundance of Bacteroidaceae,Prevotellaceae,Helicobateraceae,Tannerellaceae in the FMT group(P<0.05),and a significant decrease in the abundance of Lachnospiraceae and Deferriaceae(P<0.05),the abundance of Bacteroidaceae in the HDN group increased significantly(P<0.05),and the abundance of Lachnospiraceae,Lactobacillaceae,and Deferribacteraceae decreased significantly(P<0.05).4)In the HD group,the m RNA expressions of ZO-1,Claudin-1 and Occludin in the jejunum were significantly decreased(P<0.01),while the m RNA expressions of IL-1α,IL-1β and TNF-α were significantly increased(P<0.01).The jejunal ZO-1,Claudin-1,Occludin,IL-1α,IL-1β m RNA expressions in the LD group were significantly increased and decreased(P<0.01).In the FMT group,the m RNA expressions of ZO-1,Occludin,Claudin-1 and MUC2 in the jejunum were significantly increased(P<0.01),and the m RNA expressions of TNF-α,IL-1β and IL-1α were significantly decreased(P<0.01).In the HDN group,the m RNA expression of jejunal Occludin was significantly increased(P<0.05),and the m RNA expression of TNF-α,IL-1β and IL-1α was significantly decreased(P<0.01).In summary,under the conditions of this test,high-fat feeding was not conducive to animal intestinal tissue to maintain normal morphology,which could significantly damage the intestinal barrier structure and affect its normal function;moderate starvation feeding was beneficial to intestinal tissue morphology,and enhance the intestinal immune barrier function,but can reduce the animal’s intestinal tight connection structure;fecal microbiota transplantation and diet transformation could effectively improve or alleviate the damage caused by high-fat feed intake to the intestinal barrier,but the effect of fecal microbiota transplantation was better than the effect of changing diet.