가금류의 Salmonella gallinarum 감염에 대한 Lactobacillus paracasei KLB58의 방어능

초록

Fowl typhoid which is caused by Salmonella, is acute or chronic communicable disease with high mortality rate by sepsis in every age of fowls including chicken and turkey. Recently probiotics are of great interest because antibiotic uses are not allowed anymore in fowl industry. In this study, 108 Lactobacillus strains that had been previously isolated in our laboratory were screened for antibacterial activity against Salmonella gallinarum and Salmonella enteritidis as fowl pathogenic indicator. Twenty one lactobacilli strains showed high in vitro antibacterial activity against S. gallinarum and S. enteritidis. They also showed high antibacterial activity against Escherichia coli, Salmonella typhimurium, Staphylococcus aureus, Listeria monocytogenes, and Gardnerella vaginalis. Among these, KLB39 and KLB58 were selected because they maintained relatively high activity after pH adjustment. As a result of 16S rRNA gene sequencing, they were identified as L. salivarius subsp. salivarius and L. paracasei subsp. paracasei, respectively. The mode of action by two lactobacilli strains was likely being bacteriostatic, as the viability of pathogens did not increase without reduction. In a pre-challenge test with specific pathogen free (SPF) chicken, live lactobacilli preparation (KLB39 and KLB58 mixture) did not affect negatively on spawning rate, and the average of body weight gain was not significantly different from control group. By in vivo challenge test on chickens we demonstrated that the death rate of chickens (13.3%) that were injected with KLB58 after S. gallinarum injection was significantly lower than chickens (40%) that were injected by S. gallinarum without KLB58 co-injection. Further studies are underway as we expect that KLB58 could be used as probiotics for prevention of salmonella infection in fowl industry.

키워드