The Study On The Anti-infection Effects Of Life-profitable Characteristic By Lactic Acid Bacteria Separated From Swine

This test randomly selected2strains from32strains of lactic acid bacteria that were separated from the30day-age pigs’intestine and named them as LZ1and LZ2.Then we did the identification of traditional Bacteriology, Molecular biology and16S rRNA.Then we tested the thalli and metabolism products of the LAB to do the in vitro bacteriostasis for the usual pathogenic bacterium and their bearing of acid and bile salts. Then we did the in vivo bacteriostasis experiment using the mice as the model with the LZ1and LZ2strains and the escherichia coli K88strain sued as indicator with the method of ERIC-PCR to testify the bacteriostasis effects of the LZ1and LZ2strains. Meanwhile, we drenched mice with different doses of LZ1or LZ2strain and detected the content of IL-2, IL-4, IFN-y and TNF-a in blood of mice with the ELISA method and detected the change of growth regularity of CD3+、 CD4+、 CD8+、 CD28+T cells in peripheral blood of mice with the method of Flow Cytometry.The results showed that the result of the traditional Bacteriology Identification was same as the16SrRNA’s. The result shows that metabolite of the6strains of lactobacillus we have screened have strong bacteriostasis ability, whereas the live thallus has no inhibition activity on pathogenic bacteria; meanwhile, the bacteriostasis ability gradually decreased with the increase of pH value and finally disappeared in the weak acid and neutral condition. At equal pace, the existence of pepsin and trypsin rarely influenced the bacteriostasis ability of metabolite.The in vivo anti-infection experiment had showed that we could screened the LAB we had fed and found no K88existed in the intestine of mice when we had stopped feeding for5days.The content of IL-2in blood of mice of all the LZ1and LZ2groups were extremely significant higher than that of the control group at the day of10th、20th and30th(p<0.01). The content of IL-4in blood of mice of the LZ1and LZ2low-dose and middle-dose groups were higher than that of the control group at the day of10th、20th and30th without difference (P>0.05). The content of IFN-y in blood of mice of the LZl low-dose and middle-dose groups were extremely significant higher than that of the control group at the day of10th,20th and30th(p<0.01). The content of IFN-γ in blood of mice of the LZ2low-dose group were significant higher than that of the control group at the day of10th、20th and30th(p<0.05). The content of TNF-α in blood of mice of the LZ1low-dose and high-dose groups were extremely significant lower than that of the control group at the day of10th、20th and30th(p<0.01). The content of TNF-a in blood of mice of the LZ2low-dose group was extremely significant higher than that of the control group at the day of10th and30th(p<0.01).The content of CD3+T cells of mice of all the LZl groups were extremely significant lower than that of the control group at the day of10th (p<0.0l). The content of CD3+T cells of mice of the LZ2middle-dose and high-dose groups were extremely significant lower than that of the control group at the day of20th and30th (p<0.0\). The content of CD4+T cells of mice of the LZ1middle-dos group was significant lower than that of the control group at the day of10th、20th and30th (p<0.05). The content of CD4+T cells of mice of the LZ2middle-dose and high-dose groups were significant lower than that of the control group at the day oflOth and30th (p<0.05). The content of CD8+T cells of mice of the LZ1low-dose and high-dose groups were significant lower than that of the control group at the day oflOth (p<0.05). The content of CD8+T cells of mice of all the LZ2groups were extremely significant lower than that of the control group at the day oflOth and20th (p<0.01). The content of CD28+T cells of mice of all the LZ2groups were extremely significant higher than that of the control group at the day ofl Oth (P<0.01).