Meeting Abstract

P1.35  Tuesday, Jan. 4  Seasonal myostatin expression patterns in migratory birds PRICE, E.R.*; BAUCHINGER, U.; ZAJAC, D.M.; CERASALE, D.J.; MCFARLAN, J.T.; GERSON, A.R.; MCWILLIAMS, S.R.; GUGLIELMO, C.G.; University of Western Ontario; University of Rhode Island; University of Western Ontario; Cornell University; University of Guelph; University of Western Ontario; University of Rhode Island; University of Western Ontario eprice3@uwo.ca

Seasonal changes in organ sizes commonly occur in migratory birds, and may include changes in gut size and flight muscle mass. The mechanism by which these seasonal changes are controlled is unknown. Myostatin is a known inhibitor of muscle growth, particularly in mammals. We investigated myostatin mRNA expression in avian pectoralis muscle in three contexts: a) wild white-throated sparrows (Zonotrichia albicollis) in wintering and migratory seasons, b) captive photoperiod-manipulated white-throated sparrows in ‘wintering’ or ‘migratory’ (Zugunruhe) condition, and c) trained or untrained European starlings (Sturnus vulgaris). Flight muscle mass was greater in migratory and trained birds, and we predicted that myostatin expression would be lower in those groups. However, myostatin expression was generally higher in migratory and trained birds. Other mechanisms may therefore be more important in controlling these seasonal changes in muscle mass. Additionally, we describe several splice variants of myostatin which appear to be conserved across birds.