[The effect of Lactobacillus salivarius administration on coliform bacteria and enterococci in the crop and cecum of broiler chickens].

A rifampicin-resistant Lactobacillus salivarius 51R was isolated from chicken caeca and administered orally to newly hatched broiler chickens. The resistance to rifampicin enabled us to differentiate the administered organism from indigenous strains. First day after inoculation, L. salivarius 51R dominated among lactobacilli in the crop and caeca of inoculated chickens and its counts were slightly over 7 log c.f.u. per 1 g of digesta even after 10 days. L. salivarius significantly (P < 0.01) lowered counts of enterococci and coliforms in the crop during the whole experimental period (10 days). Effects of L. salivarius administration on caecal counts other than lactobacilli were generally small. The influence of Lactobacillus strain used to species composition of enterococci and coliforms were also observed. 105 strains of enterococci and 96 strains of coliforms isolated from the crop and caeca of both control and experimental groups were characterized using identification sets and computer program. Regarding, enterococci, 63% was identified to the species level, 31% to the genus level, and 6% was not identified. Regarding coliforms, 48% was reported to the species level, 25% to the genus level, and 26% was not identified. The most prevalent species among the enterococci was E. faecalis and among the coliforms E. coli. 24 h after the administration of L. salivarius 51R there was significantly higher (P < 0.05) occurrence of E. faecalis (57% out of all enterococcal isolates) in experimental group than those in the control group (31% out of all enterococcal isolates). The perspectives in the control of pathogens in young chickens via probiotics was discussed.