Effects Of Nutrition On The Recovery And Metabolism Of Intestinal Flora In Mice With Intestinal Flora Imbalance

Objective: To explore the effects of different nutrient interventions on intestinal flora composition and body metabolism.Methods: Thirty-six eight-week-old C57 BL /6J male mice were selected and fed adaptively for three days.The mice were randomly divided into two groups,namely,the normal group(N)(n=6)and the model group(M)(n=30).The mice in group M were continuously fed with the antibiotic ceftriaxone sodium at a dose of 8g /kg for 1w,and the mice in group N were fed with the same dose of normal saline in the same way.During the period of administration of the antibiotic,all groups ate and drank normally.After 1 week,the administration was stopped.After confirming the imbalance of intestinal flora in group M mice,the mice in group M were randomly divided into five groups,namely,natural recovery group(NR),high fiber group(HFI),high protein group(HP),high fat group(HFA)and high sugar group(HS),with six in each group.Group N and NR continued to eat and drink water normally;HFI group,HP group and HFA group were fed with high fiber feed,high protein feed and high fat feed respectively,and drank water normally;HS group was fed with common feed and drank 60% sucrose solution.The feces of mice were collected at a fixed time every week to observe the changes of fecal morphology,and DNA was extracted,and then PCR-DGGE gel electrophoresis was used for preliminary observation.The significant points of indicators were selected for 16 srRNA high-throughput gene sequencing analysis to observe the changes of intestinal flora of mice;The content of short chain fatty acids in feces of mice in high fiber group was detected.The body weight,food intake,water consumption and fasting blood glucose(FPG)of mice were measured at a fixed time every week.After 6 weeks of nutrition intervention,insulin(INS),total cholesterol(CH)and homocysteine(Hcy)were detected by ELISA in mice’s fasting serum to observe the changes of glucose and lipid metabolism.Results:1.Changes in metabolic indicators of mice1.1 Effect on FPG of mice: FPG of mice in group M remained at normal level after oral administration of antibiotics.After the first week of nutritional intervention,FPG of each nutritional intervention group was higher than that of N group and NR group,with statistical differences.1.2 Effect on the INS concentration and HOMA-IR index of mice: After 6 weeks of nutritional intervention,the INS concentration and HOMA-IR index of mice in NR group remained at normal level,the INS concentration of mice in HFI group and HP group was significantly lower than that in N group and NR group(P<0.001),the INS concentration of mice in HFA group was higher than that in N group(P<0.05),and the INS concentration of mice in HS group was lower than that in NR group(P<0.001),both of which were statistically significant.The HOMA-IR index of HFI group was lower than that of N group(P<0.05).1.3 Effect on the concentration of CH in mice: After 6 weeks of nutritional intervention,the concentration of CH in NR group,HFI group,HP group and HS group remained at normal level,while the concentration of CH in HFA group increased significantly,with significant difference between each group(P<0.001).1.4 Effect on the Hcy concentration of mice: After 6 weeks of nutritional intervention,the Hcy concentration of mice in NR group and HFA group remained at normal level,and the Hcy concentration of mice in HFI group,HP group and HS group was lower than that in N group and NR group,with statistical difference(P<0.05).1.5 Effect of high-fiber diet on short-chain fatty acids in mouse feces: After 6 weeks of high-fiber diet,the content of acetic acid in mouse feces did not change significantly,the content of propionic acid decreased significantly(P<0.001),and the content of butyric acid increased significantly(P<0.001).2.Effect on the morphology of mouse fecesAfter nutritional intervention,the feces of mice in HFI and HFA groups became lighter,and the color became darker after 4 weeks of intervention,but still lighter than those in N and NR groups;After 6 weeks of nutrition intervention,the stool volume of NR group,HFI group and HP group increased significantly,while that of HS group and HFA group decreased;The faeces of mice in N group,NR group,HP group and HS group are normal,and the faeces of mice in HFI group and HFA group are normal in appearance and contain more soft stool.3.Effect on the changes of intestinal flora in miceAfter 1 week of antibiotic administration,the Shannon index and abundance of intestinal flora in mice decreased significantly(P<0.001).After 2 weeks of nutritional intervention,the diversity of intestinal flora in NR group,HFI group,HFA group and HS group returned to normal level;After 6 weeks of nutrition intervention,compared with the NR group,high fiber diet can promote the growth of Plavobacter and Plavobacter,and high protein diet can promote the level of Erysipelotrichales and family,Ileibacterium and Clostridia＿The growth of UCG-014 at the level of order,family and genus;High-sugar diet can promote the growth of Erysipelotrichales flora,family level and Ileibacterium flora.Conclusion:1.The intestinal flora of healthy mice has the ability of self-recovery after being administrated with ceftriaxone sodium for 1 week;2.The recovery of intestinal flora in mice with intestinal flora imbalance was delayed by high protein diet within 2 weeks,but after 6 weeks of intervention,the abundance of intestinal flora in mice with high protein group was better than that in natural recovery group;3.After nutritional intervention on mice with intestinal flora imbalance,the feces of mice on the normal diet,high-protein diet and high-sugar diet are normal,and the feces of mice on the high-fiber diet and high-fat diet are normal in appearance and contain more soft stools and the color becomes pale;4.Inappropriate high-fiber diet,high-protein diet and high-sugar diet can reduce the fasting serum insulin and homocysteine concentrations in mice with intestinal flora imbalance;5.High-fiber diet can promote the growth of the family of Plavobacter and the genus of Plavobacter.High-protein diet can promote the level of Erysipelotrichales and the family,the genus of Ileibacterium and Clostridia＿The growth of UCG-014 at the level of order,family and genus;High-sugar diet can promote the growth of Erysipelotrichales flora,family level and Ileibacterium flora.