Isolation,Identification And Preliminary Application Of Lactobacillus Reuteri From Alopex Lagopus

As a new type of feed additive that is environmentally friendly,non-toxic,harmless,side-effect-free and residue-free,probiotic preparations are increasingly used in animal industry.Lactic acid bacteria,as one of the common strains of probiotic preparations,have a series of probiotic role such as antibacterial,bowel adjustment and growth promotion.In this experiment,the identification of LAB in Alopex lagopus’ s intestinal tract was carried out.And its biological characteristics and future application were studied so as to provide a theoretical basis for the development of Alopex lagopus and even canidae origin microbiological preparations.In this experiment,main 3 samples of A.lagopus’ s colon contents were collected for the separation of LAB,and the analysis of morphological characteristics,physiological and biochemical characteristics of bacteria,and by the method of I6 S rRNA molecular identification technology were identified,and finally 1 strain of Lactobacillus reuteri ZJBF006 was identified.Through the growth test,it was found that the strain ZJBF006 can quickly enter the logarithmic growth period after 3 hours,and enter the stable growth period after 8 hours.At the same time,the pH value of the bacterial solution rapidly dropped to 3.89 within 8 hours,and finally stabilized at around 3.70.Through acid resistance test,artificial gastrointestinal fluid tolerance test and bile salt tolerance test,it was found that the strain ZJBF006 can maintain good growth in an acid environment with pH≥4.0,and the tolerance rate of artificial gastric juice and intestinal fluid is higher than 90%,The tolerance rate of bile salts is higher than 88%,which meets the basic requirements of colonization in the gastrointestinal tract.Through surface hydrophobicity test,self-aggregation test and adhesion test to small intestinal epithelial cells,it was found that strain ZJBF006 is moderately hydrophobic,but does not have selfaggregation ability,and the adhesion rate to small intestinal epithelial cells is(11.87 ±2.10)CFU/cell.Through in vitro bacteriostasis tests,it was found that strain ZJBF006 has a good inhibitory effect on Escherichia coli,Salmonella and Staphylococcus aureus,and has a certain inhibitory effect on Bacillus subtilis but a weaker inhibitory ability.The antibiotic sensitivity test found that strain ZJBF006 is sensitive to penicillin G,cephalosporin,ciprofloxacin,chloramphenicol and clindamycin.Through the DPPH free radical scavenging test,it was found that the removal rate of strain ZJBF006 to DPPH free radical was(32.84±0.09)%.Through the study of safety evaluation,it was found that the strain ZJBF006 is not pathogenic to mice.By establishing bacterial enteritis caused by Salmonella typhimurium and ulcerative colitis induced by DSS in rats,the preventive effect of Lactobacillus reuteri ZJBF006 on these two common enteritis was studied.The research results show that after using ZJBF006 for the treatment or prevention of bacterial enteritis and ulcerative colitis,rats can show a certain improvement trend in three aspects of body weight,blood routine indicators and serum cytokine indicators,which shows that ZJBF006 Both types of enteritis have a certain protective effect.In summary,the isolated Lactobacillus reuteri ZJBF006 has good probiotic properties,and has a certain preventive effect on bacterial enteritis and ulcer caused by Salmonella typhimurium.This strain has the potential to become a candidate strain of probiotic preparations of A.lagopus and even canine origin.