English

Levkut Jr M,Levkutová M,Žitňan R,Ševčíková Z,Lauková A,Karaffová V,Levkut Sr M,Strompfová V,Revajová V,Herich R

doi:10.5897/jvmah2015.0506

Abstract

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.

Highlights

Enteric salmonellosis is a major foodborne disease caused by Salmonella and its serovars, the most common being Enteritidis and Typhimurium
The results in the current study revealed that administration of E. faecium EF55 had immunostimulatory effect on the number of heterophils in the peripheral blood of the chicks infected with S
Our results suggest that the increased tendency of mRNA expression IL-15 and IL-17 could participate in attraction of mucosal immunocompetent cells including heterophils and lymphocytes into intestinal mucosa

Summary

Introduction

Enteric salmonellosis is a major foodborne disease caused by Salmonella and its serovars, the most common being Enteritidis and Typhimurium. Chicken is recognized as one of the most important reservoir of Salmonella. The colonization of the chicken gut by S. enterica could result in the contamination of the environment and food chain. Potential probiotic strains have been found among the intestinal microbiota of food producing animals. Some bacteria have been shown to exert antimicrobial activity against enteric pathogens due to the production of bacteriocins and bacteriocin-like molecules. The E. faecium EF55 was shown to produce a bacteriocin-like substance, and the inhibitory activity of this probiotic strain of bacteria was reported against number of enteropathogenic bacteria, including S. enterica (Levkut et al, 2009)

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Results

Conclusion