Passive maternal exposure to environmental microbes selectively modulates the innate defences of chicken egg white by increasing some of its antibacterial activities

BMC Microbiology

Research Article

Emmanuelle Helloin¹  Nicolas Guyot²  Larbi Bedrani²  Yves Nys²  Sophie Réhault-Godbert² 

[1]UMR1282, Infectiologie et Santé Publique, Institut National de la Recherche Agronomique, Nouzilly, France

[2]UR83 Recherches Avicoles, Institut National de la Recherche Agronomique, Nouzilly, France

关键词: Chicken;    Egg;    Germ free;    Innate immunity;    Antimicrobial protein;   

DOI  :  10.1186/1471-2180-13-128

 received in 2012-12-20, accepted in 2013-05-28,  发布年份 2013

来源: Springer

【 摘 要 】

BackgroundEgg defence against bacterial contamination relies on immunoglobulins (IgY) concentrated in the yolk and antimicrobial peptides/proteins predominantly localized in the egg white (EW). Hens contaminated with pathogenic microorganisms export specific IgYs to the egg (adaptative immunity). No evidence of such regulation has been reported for the antimicrobial peptides/proteins (innate immunity) which are preventively secreted by the hen oviduct and are active against a large range of microbes. We investigated whether the egg innate defences can be stimulated by the environmental microbial contamination by comparing the antimicrobial activity of EW of hens raised in three extreme breeding conditions: Germ-free (GF), Specific Pathogen Free (SPF) and Conventional (C) hens.ResultsThe difference in the immunological status of GF, SPF and C hens was confirmed by the high stimulation of IL-1β, IL-8 and TLR4 genes in the intestine of C and SPF groups. EW from C and SPF groups demonstrated higher inhibitory effect against Staphylococcus aureus (13 to 18%) and against Streptococcus uberis (31 to 35%) as compared to GF but showed similar activity against Salmonella Enteritidis, Salmonella Gallinarum, Escherichia coli and Listeria monocytogenes. To further investigate these results, we explored putative changes amongst the three main mechanisms of egg antimicrobial defence: the sequestration of bacterial nutrients, the inactivation of exogenous proteases and the direct lytic action on microorganisms. Lysozyme activity, chymotrypsin-, trypsin- and papain-inhibiting potential of EW and the expression of numerous antimicrobial genes were not stimulated suggesting that these are not responsible for the change in anti-S. aureus and anti-S. uberis activity. Moreover, whereas the expression levels of IL-1β, IL-8 and TLR4 genes were modified by the breeding conditions in the intestine of C and SPF groups they were not modified in the magnum where egg white is formed.ConclusionsAltogether, these data revealed that the degree of environmental microbial exposure of the hen moderately stimulated the egg innate defence, by reinforcing some specific antimicrobial activities to protect the embryo and to insure hygienic quality of table eggs.

【 授权许可】

Unknown   
© Bedrani et al.; licensee BioMed Central Ltd. 2013. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.