In vitro selection of potential immunomodulatory multispecies lactic acid bacteria in broilers

Modulation of host immunity is one of the proposed benefits of the consumption of probiotics. In this study a total of 26 lactic acid bacteria belonging to eight different species were isolated from chicken gut. These twenty six probiotic organisms were characterized by Gram's staining, biochemical methods using 21 sugars, pH tolerance and bile salt tolerance test. These probiotic organisms were identified using PCR amplification of 16S-23S spacer region and sequencing analysis. Based on the sequencing data, 6 different species were found to exist namely Enterococcus faecalis; Enterococcus faecium, Enterococcus hirae, Weissella cibaria, Lactobacillus salivarius, Pediococcus acidilactici. To select the immunomodulatory probiotic bacteria, the scoring index was established based on different chicken cytokine expression and B and T cell receptor expression studies. According to scoring index, Pediococcus acidilactici, Lactobacillus salivarius and Weissellacibaria showed highest levels of fold increase in the expression of Th1 cytokines viz. IL2, IL 12p40, IL1 beta and TNF alpha. Enterococcus faecalis and Enterococcus faecium showed highest levels of fold increase in the expression of Th-2 cytokines viz. IL 4, IL10, TGF beta and IL6.