Isolation Of Lactic Acid Bacteria From Chicken Intestinal And Studies On Its Probiotic Properties

In this research,two strains of lactic acid bacteria were isolated from chicken intestine.These two strains were eventually identified as Lactobacillus brevis and Enterococcus faecalis by biochemical and molecular biological identification.Then the two strains were conducted on inhibition test,acid tolerance test and bile salt tolerance test.The mice were fed with milk suspension made of these two strains and vaccinated by E.coli K88,their intestinal contents were separated and purified,their DNA were extracted and amplified by PCR analysis.Use ELISA method to determine IL-2,TNF-a,IL-4,IFN-γ levels in serum,IgG content and SIgA content in the gut of the mice fed with the two separated strains.Use FCM to determine the T cells CD3+, CD4+, CD8+, CD28+content in the blood and calculate the change of CD4+/CD8+ratio.The results show that:1.The metabolites and live bacteria of the two separated strains have a strong antibacterial activity under different pH conditions,thus the mycelia was not;the group dealed by enzyme have no significant differences with the blank group.2.The two strains in this test can all withstand a certain environment to porcine bile salt and bovine bile salt.3.The two strains were all have some inhibit and eliminate ability and can all survive for a long period in the intestine.4.After fed with these two strains,the content of IL-2,TNF-a,IL-4,IFN-y in serum and the level of IgG, SIgA were significantly increased compared with the blank group.5.The two tested strains can improve T cells CD3+, CD4+, CD8+, CD28+content in peripheral blood and optimize CD4+/CD8+ratio.