Meeting Abstract

2.6  Sunday, Jan. 4  Antibacterial proteins in eggs as a marker of disease risk in different environments HORROCKS, N.*; HINE, K.; MATSON, K.D.; TIELEMAN, B.I.; University of Groningen, The Netherlands; University of Groningen, The Netherlands; University of Groningen, The Netherlands; University of Groningen, The Netherlands n.p.c.horrocks@rug.nl

Bird eggs contain several antibacterial proteins that likely help protect developing embryos from microbial infections. These proteins, which are located predominantly in the albumen, may be particularly important in protecting eggs from infection in microbe-rich environments or under other conditions favourable to bacterial penetration of the shell and membranes. Ovotransferrin, lysozyme and avidin are three such proteins that can be measured using simple assays. Together these proteins constitute nearly 20% of the total protein composition of chicken albumen, and have been shown to be present in the albumen of other avian eggs too. The degree to which their concentrations vary, and how this may reflect broader differences in life history and disease pressure remains unclear however. To investigate these relationships, we collected eggs from 7 species of larks (Alaudidae) living in very dissimilar habitats (Saudi Arabian desert, high altitude Afghanistan, lowland temperate Netherlands). Larks are ground-nesting passerines with open-cup nests and their eggs are potentially exposed to a wide variety of microbes from both the soil and the air. We measured levels of ovotransferrin, lysozyme and avidin in the albumen of these eggs and compared values across species and environments. Here we present our findings and discuss how the quantification of egg antibacterial proteins relates to our broader goal of understanding how the disease risks in different environments shapes the evolution of physiological systems.