Isolation And Preliminary Application Of Biofilm Lactic Acid Bacteria From Pig Manure

As an important member of the traditional aquaculture industry,the pig industry has a large share in the meat market in China.With the large-scale and intensive farming of the pig industry,the phenomenon of abuse of antibiotics and drugs is widespread in the pig industry.In order to screen lactic acid bacteria strains with reliable animal safety,biofilm formation and bacteriostatic properties and good biological properties,in order to be suitable for the development and production of lactic acid bacteria probiotic preparations,In this study,119 Gram-positive suspected lactic acid bacteria isolates were screened from the selection of healthy piglet feces from the breeding base of Jilin Agricultural University.After the detection of biofilm formation ability and common pathogen bacteria inhibition experiments,7 isolates with good biofilm formation ability and antibacterial ability were selected and named as Z-01,Z-02,Z-03,Z-04,Z-05,Z-06 and Z-07.After molecular biological identification,it was confirmed that Z-01,Z-02,Z-03,Z-04 and Z-05 were Enterococcus faecium,Z-06 was Enterococcus faecalis,and Z-07 was Lactobacillus acidophilus.In order to screen and obtain lactic acid bacteria with good biological characteristics,through the tests of acid production ability,bile salt resistance test,high temperature test,trypsin test,acid resistance test and common antibacterial drug sensitivity test,the following conclusions are drawn: The acid production capacity of 7 strains of lactic acid bacteria is relatively close,and the pH value of the supernatant is between 3.44 and 4.25;At 0.4% bile salt concentration,Z-07 survival rate was 24%,Z-03 survival rate was 19.1%,and the survival rate of the remaining 5 isolates was between 10% and 15%;The OD values of the isolates at 50 °C,55 °C and 60 °C showed no significant change compared with 37 °C,which proved that the 7 isolates were tolerant to high temperature environment;The survival rate of 7 strains was maintained between 77% and 94% under the influence of the highest concentration of 1.4% trypsin;7 strains in the environment with a pH of 2.0,the Z-04 survival rate was up to 44.6%;Z-03 and Z-07 showed moderate sensitivity to ampicillin,while Z-01,Z-02,Z-04,Z-05 and Z-06 showed resistance to ampicillin.Z-03 and Z-07 with excellent biological characteristics were selected from 7 isolates,and the animal safety test,the Salmonella semi-lethal lethal test and the lactic acid bacteria in vivo bacteriostatic test were carried out.The results are as follows: The two isolates Z-03 and Z-07 have reliable animal safety and have good probiotic effects;It has certain antibacterial protection against Salmonella CVCC-503,Enterococcus faecium Z-03 and Lactobacillus acidophilus Z-07.This study successfully screened Enterococcus faecium Z-03 and Lactobacillus acidophilus Z-07 with good antibacterial ability and biofilm formation ability.Its excellent biological properties provide a theoretical basis for its development and utilization of probiotic preparations.