Meeting Abstract

19.3  Tuesday, Jan. 4  Concentrations of antibacterial proteins in eggs: an index of environmental microbial pressure? HORROCKS, N.P.C.*; WHEELER, E.; MATSON, K.D.; HEGEMANN, A.; TIELEMAN, B.I.; University of Groningen; University of Illinois at Urbana-Champaign; University of Groningen; University of Groningen; University of Groningen n.p.c.horrocks@rug.nl

Environmental variation in microbial communities and the pathogen pressures they exert are an important factor in shaping the immune defences of organisms. For birds, the egg stage is a particularly vulnerable phase: the immobile egg is exposed to microbes from both the nest environment and the incubating parent from which it cannot escape. To protect the developing embryo from microbial invasion, eggs possess physical (the eggshell) and chemical (antibacterial proteins in the albumen) defences. Antibacterial proteins may be particularly important in protecting eggs from infection in microbe-rich environments or under conditions favourable to bacterial penetration of the shell, such as damp and humid environments. These may also be environments that possess greater risk of infection for adult birds. We hypothesised that levels of antibacterial proteins in eggs may therefore be a good indicator of how birds perceive the ‘pathogenicity’ of their environment and provide an index of broader environmental pathogen pressure. Using eggs from a variety of species and environments, we measured concentrations of antibacterial proteins and related them to different aspects of environmental variation. We present the results of our analyses and compare our findings to measures of immune function in adult birds living in the same environments.