Meeting Abstract
140.5 Monday, Jan. 7 The Long-term Effects of Early-Life Stress on Metabolic Rates, Body Composition, and Body Size in Song Sparrows SCHMIDT, K.L.*; MACDOUGALL-SHACKLETON, E.A.; MACDOUGALL-SHACKLETON, S.A.; Western University, London, ON; Western University, London, ON; Western University, London, ON kschmi5@uwo.ca
Variation in the pre- and postnatal environments can have long-term effects on adult phenotype. In particular, exposure to stressors during development can lead to long-term changes in physiology. These changes may predispose individuals to disease, especially disorders involving energy metabolism. In addition, by permanently altering metabolic rates and energy requirements, such effects could have important fitness consequences. We determined the effects of early-life food restriction and corticosterone (CORT) treatment on adult metabolic rates, body composition (assessed via quantitative magnetic resonance), and body size in song sparrows (Melospiza melodia). Nestlings were hand-raised in captivity from 3 days of age (d3) and exposed to treatments (ad libitum food, food restriction, or CORT-treatment) from d7- d60. Both experimental treatments had sex-specific effects on standard metabolic rates (SMR). Females exposed to food restriction or CORT treatment during development had higher SMRs in adulthood than control females, but neither stressor affected SMR in males. There were no effects of either treatment on adult body composition (lean or fat mass) or peak metabolic rates. Although both experimental treatments affected nestling growth there was no long-term effect of either treatment on adult body size. In addition, despite the fact that birds were raised in captivity from an early age (d3), their adult mass was positively related to the mass of their genetic father. This suggests that body size may be a canalized trait in this species. Our results also suggest that early-life stress may have sex-specific programming effects on metabolic rates and energy expenditure in song sparrows.
