Are antimicrobial defences in bird eggs related to climatic conditions associated with risk of trans-shell microbial infection?

Research output: Contribution to journalArticle

Abstract

Introduction: All bird eggs are exposed to microbes in the environment, which if transmitted to the developing embryo, could cause hatching failure. However, the risk of trans-shell infection varies with environmental conditions and is higher for eggs laid in wetter environments. This might relate to generally higher microbial abundances and diversity in more humid environments, including on the surface of eggshells, as well as the need for moisture to facilitate microbial penetration of the eggshell. To protect against microbial infection, the albumen of avian eggs contains antimicrobial proteins, including lysozyme and ovotransferrin. We tested whether lysozyme and ovotransferrin activities varied in eggs of larks (Alaudidae) living along an arid-mesic gradient of environmental aridity, which we used as a proxy for risk of trans-shell infection. Results: Contrary to expectations, lysozyme activity was highest in eggs from hotter, more arid locations, where we predicted the risk of trans-shell infection would be lower. Ovotransferrin concentrations did not vary with climatic factors. Temperature was a much better predictor of antimicrobial protein activity than precipitation, a result inconsistent with studies stressing the importance of moisture for trans-shell infection. Conclusions: Our study raises interesting questions about the links between temperature and lysozyme activity in eggs, but we find no support for the hypothesis that antimicrobial protein deposition is higher in eggs laid in wetter environments.

Details

Authors
  • Nicholas P. C. Horrocks
  • Kathryn Hine
  • Arne Hegemann
  • Henry K. Ndithia
  • Mohammed Shobrak
  • Stephane Ostrowski
  • Joseph B. Williams
  • Kevin D. Matson
  • B. Irene Tieleman
External organisations
  • University of Groningen
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Biological Sciences

Keywords

  • Antimicrobial, Aridity, Humidity, Egg albumen, Lark, Lysozyme, Ovotransferrin
Original languageEnglish
Article number49
JournalFrontiers in Zoology
Volume11
Publication statusPublished - 2014
Publication categoryResearch
Peer-reviewedYes
Externally publishedYes