An assessment of the aggregation and probiotic characteristics of Lactobacillus species isolated from native (desi) chicken gut

Themicroflora within a chicken's gastrointestinal tract (GIT) has extensive bacterial diversity and may be a good source for the isolation of effective probiotic candidates. The resistance of desi chickens to various biotic and abiotic stresses is related to the presence of lactic acid bacteria (LAB) in their digestive system. In this study, LAB were isolated and cultured from the caecum contents of desi chickens and identified based on their phenotypic characters and rDNA gene sequences. The aggregation capability of the isolated Lactobacillus species was tested and those strains showing strong aggregation were further tested to see if they were better able to withstand the stress of GIT digestive conditions. The results demonstrated significant variation in aggregation ability and GIT stress tolerance. The autoaggregation potential of the strains was not correlated with their cell surface hydrophobicity but was found to be linked to coaggregation ability with pathogens. No potentially harmful enzymatic activities were observed in the poultry-derived LAB strains and the ones with good aggregation potential were susceptible to most common antibiotics. This study proved that native chickens can be a good source for isolating potentially effective probiotic LAB species. Furthermore, the aggregation potential among Lactobacillus species was highly strain specific and did not correlate with their ability to survive the stresses of digestion in the GIT.