Study On The Regulation Of Cold-resistant Combined Bacteria LB On Cold-stressed Intestinal Flora

In this experiment,different probiotic strains were screened,and probiotic strains with strong tolerance were selected to be enriched in mung bean saccharification solution,and ice cream was used as carrier to explore the change of survival state during the freezing process and after entering the human body.The main research contents of the inhibitory effect of chilling intestinal irritable diarrhea and the intestinal flora are as follows:1.Screening of strains:Screening of four strains of Lactobacillus plant arum Lp-01,Lactobacillus bulgaricus Lb-01,Bifidobacterium adolescentis Bba-02,and Bifidobacterium longum BL-01 through freezing and resuscitation,different pH environments and The treatment of different choline salt concentrations in the environment,screening for strains with higher resistance.Upon investigation,Lactobacillus plantarum Lp-01 and Bifidobacterium adolescentis Bba-02 were well tolerated and named as combinatorial LB,which will be used in subsequent cryopreservation experiments.2.Optimization of enrichment conditions of combinas LB:optimization of enrichment conditions for different mung bean juice concentrations,different high-temperature amylase additions,different culture temperatures and different culture times,and optimized the number of viable cells in the culture solution as the response value The conditions of Jiafu collection were as follows:the inoculation ratio of Lactobacillus plantarum Lp-01 to Bifidobacterium adolescentis Bba-02 was 1:1,the culture temperature was 39.5?,and the culture time was 18.5 h.Under the optimized scheme,the actual number of viable cells in the culture solution was obtained.It was 6.79 × 1011 cfu/mL.3.Survival status of the combined bacteria LB during freezing:The survival rate of the combined bacteria LB with ice cream as a carrier,and the ability of the strain to resist acid and bile salts were determined.LB ice cream was stored at-20? and-40?,respectively,and the order of the LB in the ice cream in 90 d decreased from 9.94 to 7.18 and 6.79,respectively.The activity of the strain increased first and then increased with the increase of the number of frozen storage days,and then gradually became stable.After 65 days,the acid resistance and choline-resistant ability of the probiotics frozen at the two temperatures gradually stabilized.The W values are stable at around 20%and 72%-73%,respectively.4.Inhibition of cold diarrhea by combined bacteria LB:eating cold food can cause diarrhea in some mice,but the combined bacteria LB can alleviate the symptoms of diarrhea in cold-sensitive mice.During the experiment,the stool rate of the high-dose group decreased by 3.11%,and the diarrhea index(10-1)decreased from 0.52 to 0.19,which was decreased by 0.33.The decrease was the largest in each group,indicating that the concentration of probiotics in the dose range was higher.The stronger the inhibitory effect on cold diarrhea in mice.5.High-throughput analysis of the effect of combinatorial LB on intestinal flora of cold-fed mice:High-throughput sequencing analysis of fecal microflora in different groups of mice showed that the ACE and Chaol values were highest in the high-dose group.69987.29 and 27098.77,respectively,indicating that the abundance of intestinal flora in mice taking LB ice cream was increased compared with mice not taking probiotics.According to the OTU Venn diagram and the principal coordinate analysis,the similarity between the middle dose group and the control group was the closest,while the difference between the blank group and the control group was the largest.The intestinal flora of mice that took the combination LB decreased at the level of the door,and the proportion of the bacillus population decreased and the proportion of the phylum was increased.The genus level was composed of Lactobacillus,Escherichia,and Brout.The proportion of bacteria and the like increased,and the structure of the flora changed,indicating that the combined bacteria LB after freezing can colonize the intestine of mice and regulate the intestinal tract of mice.