| Intestinal microflora is an important factor in determining host health.Abnormal changes in intestinal microecology may lead to the occurrence of a variety of diseases.Some lactic acid bacteria have been shown to improve the intestinal environment by regulating intestinal microbiota disturbances,thereby promoting host health.Yak has the characteristics of high cold tolerance and low oxygen,and probably has a special intestinal flora.However,few studies have been conducted on the intestinal flora of yaks.Therefore,in this study,the biological characteristics of this strain of Pediococcus lactis with probiotic function were studied by using the Pediococcus lactis isolated from the intestinal tract of yaks.The effects of the strain on intestinal development and intestinal microflora were observed by ingavage treatment of mice,so as to explore its probiotic effect.The main research results of this experiment are as follows:1.Analysis of the biological characteristics of P.lactis strains,acid resistance results showed that: when the medium p H =2,the growth of P.lactis was weak,the survival rate was 20.16%;when the medium p H =3,the growth rate was better,the survival rate was higher than 29.77%;when the medium p H =4,the survival rate was 67.22%.The results of bile salt tolerance showed that the survival rate of P.lactis was 65.43%when cultured in 0.3% bile salt concentration for 6 hours.The survival rate of P.lactis strain was 49.43% when cultured for 6 hours at the concentration of 0.4% bile salt.It can be seen that this strain of Petiococcus lactate has a relatively good ability of acid and bile salt tolerance.In addition,we tested the bacteriostasis and drug sensitivity of the lactic acid pellet strain.According to the test results,the lactic acid pellet strain had good bacteriostasis to Salmonella and Escherichia coli,and most of the antibiotics selected had obvious drug resistance,and were only sensitive to florfenicol and Guitamycin.2.By comparing the development status of intestinal villi and intestinal crypt,it was found that the length of villi in the experimental group grew more rapidly and the crypt depth was shallow,indicating more mature,compared with the control group.The V/C ratio of the two groups nearly doubled,while the increase of V/C value proved the improvement of intestinal absorption capacity.The number of goblet cells and MUC2 protein in mice in the experimental group was significantly higher than that in the control group.The probiotics can affect the expression of goblet cells and mucin MUC2 secreted by goblet cells,and lactic acid bacteria can promote the expression of goblet cells and mucin MUC2,which can enhance the protection and lubrication of mucosa epithelium.It is concluded that lactic acid bacteria can promote intestinal development significantly.Secondly,by comparing the development status of intestinal villi and intestinal crypt,it was found that the length of villi in the experimental group grew more rapidly and the crypt depth was shallow,indicating more mature,compared with the control group.The V/C ratio of the two groups nearly doubled,while the increase of V/C value proved the improvement of intestinal absorption capacity.It can be seen that lactic acid bacteria have a significant promoting effect on intestinal development.3.Effects of Petiococcus lactis from yaks on intestinal flora of mice:The Pediococcus lactate used in this study can change the abundance of multiple genera in the intestinal flora of mice.Through the analysis of changes in the levels of Lactobacillus,Pediococcus,Desulfovibrio,Enterorhabdus,Alistipes,UCG 014 and other genera in the intestine,it can be confirmed that Lactobacillus can directly affect the abundance of intestinal microbes in the above six genera.Therefore,Lactobacillus may be an important factor regulating beneficial intestinal microorganisms such as Lactobacillus and Pediococcus in the intestinal tract.The Pediococcus lactis used in this study can also restore the intestinal flora of mice treated with antibiotics,and its restoration effect on the levels of genus Muribaculaceae,Enterorhabdus and Lachnoclostridium in the intestine is weaker than that of FMT.However,after the intestinal flora of mice is destroyed,the Pediococcus lactis can restore the diversity of intestinal flora of mice more than the natural restoration.In conclusion,this strain of Petiococcus lactis from yaks has a good ability of acid resistance and bile salt resistance,and has obvious drug resistance to 13 antibiotics,but the bacteriostatic ability to Salmonella and Escherichia coli is weak.Comprehensive lactic acid bacteria on the regulation of physiological indexes in the host differences found that source of yak lactic acid coccus can effectively promote the intestinal development,good regulation of intestinal flora exist pertinence in mice,and along with the increase of the genus lactobacillus can promote inhibit the growth of harmful bacteria,can restore the streptomycin disorder of mice caused by intestinal flora. |
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