Lactobacillus flora in the cloaca and vagina of hens and its inhibitory activity against Salmonella enteritidis in vitro

Lactobacilli in the cloaca and vagina of 40 normal laying hens were investigated quantitatively and qualitatively, and their ability to inhibit growth of Salmonella enteritidis (SE) was examined using a spot-the-lawn technique. All samples of cloacal contents and half the samples of vaginal mucus were positive for lactobacilli. The means ± SD of total Lactobacillus counts in the cloaca and those in the vagina were log10 5.5 +/- 1.1 and 2.5 +/- 2.6 cfu/g, respectively. In the cloaca, Lactobacillus acidophilus was isolated from 92.5% of hens, and Lactobacillus salivarius was isolated from 85.0% of hens, whereas Lactobacillus fermentum was isolated from only one hen. In the vagina, L. acidophilus and L. salivarius were isolated from 42.5% of hens. In the inhibition assay in vitro, all strains of Lactobacillus from cloacal contents and vaginal mucus inhibited growth of SE. There was a wide range of the inhibitory activity even in the same species. No difference of the growth inhibition zone was observed between lactobacilli from cloaca and those from vagina. The present study suggested that lactobacilli in the cloaca and vagina of hens might have a protective effect against SE colonization.