Dr Ian Dunn - The genetics and function of the cuticle, the eggs antimicrobial outer barrier.

Réalisation : 23 mars 2021 Mise en ligne : 23 mars 2021
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Avian eggs have a proteinaceous cuticlecovering the outside of the eggshell forming a barrier to the transmission ofmicroorganisms. Although the cuticle is similar to the organic matrix, itssecretion is separate from the organic matrix and occurs just prior tooviposition. Using NGS sequence it was possible to investigate genes that mightbe involved in cuticle deposition, which suggested that an endogenous clock maycontrol events in the uterus, including cuticle deposition. There isconsiderable variation within breeds of chicken and indeed between species inthe quantity of cuticle deposition. Around 40% of the variation within chickenbreeds is genetically determined. Environmental stressors explain some of thevariation but the remainder is not known. Within the range of natural variationthere are considerable differences in the antimicrobial protection that thecuticle affords the egg. The eggs with the best cuticle are not penetrated whenchallenged by E.coli and Salmonella. Interestingly, although the cuticleprotein had intrinsic antimicrobial activity, we could not prove that theglycosylation level was important for this activity. The cuticle is afascinating structure with antimicrobial effects but also on the shell, whichhas been rarely studied.



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