The protective effect of probiotic strain Enterococcus faecium EF55 in chicks challenged with Salmonella enterica serovar Enteritidis 147 (SE147) was assessed in caecum and blood. Quantitative reverse transcription-polymerase chain reaction (RT-PCR) detection of mRNAs of chicken intestinal mucin gene (MUC2), Interleukin (IL-15) and Interleukin (IL-17) cytokines, together with flow cytometry determination of intraepithelial lymphocytes (IEL) were investigated in caecum. White blood cell counts were measured haematologically. One-day-old chicks were divided into 4 groups. The probiotic (EF) and probiotic+salmonella groups (EFSE) received perorally 109 CFU EF55 7 days. The challenged SE and EFSE groups were single perorally infected with 108 CFU SE147 on day 4. No bacteria were given to controls (C). Administration of EF55 to chicks challenged with SE147 (EFSE group) ultimately resulted in increased number of blood heterophils, caecal IgA+ IEL, and decreased caecal expression of MUC compared to SE group on 7 days post infection (d.p.i.). Detection of IL-15 and IL-17 mRNAs cytokine level in caecum showed a tendency to their increase on 1 d.p.i. in EFSE group. The results demonstrated beneficial effect of EF55 on the expression of MUC and production of IgA+ IEL in caecum after SE147 infection. Furthermore, the results suggest certain relation between expression of cytokines, expression of MUC and IgA+ cells.
Key words: blood, chicks, immunity, infection, intestine, probiotics.
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