We measured basal (BMR) and peak metabolic rates (PMR) in juvenile and adult House Sparrows. Juvenile birds had significantly higher BMR, but lower PMR than adult birds, despite having statistically indistinguishable body masses. We then evaluated the relation between PMR and masses of central and peripheral organs and found that pectoral muscle mass best correlated with PMR in both groups, accounting for about 35% of the variation in PMR. Because citrate synthase (CS) has such major importance in affecting the first committed step in the tricarboxylic acid cycle, we characterized CS activity levels in extracted muscles to see if this better explained age-related differences in peak aerobic performance. Surprisingly, juvenile sparrows had significantly higher CS activity levels than adults (197.8 vs. 179.0 µM g−1 min−1, respectively). This higher enzyme activity in juveniles was completely offset by their significantly smaller proportion of flight musculature relative to body mass (17.7 % in adults vs. 15.3% in juveniles). Consequently, ontogenetic changes in relative sizes of organs best accounts for age-related differences in peak metabolic rate.
Skip Nav Destination
Article navigation
NotSpecified|
October 14 2011
Citrate synthase activity does not account for age-related differences in maximum aerobic performance in House Sparrows (Passer domesticus)
William Buttemer;
William Buttemer
1
School of Biological Sciences, University of Wollongong, Wollongong, NSW, 2522
Search for other works by this author on:
Claus Bech;
Claus Bech
2
Department of Biology, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
Search for other works by this author on:
Mark Chappell
Mark Chappell
3
Department of Biology, University of California, Riverside, Riverside, California 92521, USA
Search for other works by this author on:
Australian Zoologist (2010) 35 (2): 378–382.
Citation
William Buttemer, Claus Bech, Mark Chappell; Citrate synthase activity does not account for age-related differences in maximum aerobic performance in House Sparrows (Passer domesticus). Australian Zoologist 1 January 2010; 35 (2): 378–382. doi: https://doi.org/10.7882/AZ.2010.026
Download citation file:

How do RZS NSW members access the full text papers?
If you are a current RZS NSW member (with publications), please access the full text of papers by visiting https://www.rzsnsw.org.au/member-centre/publications (you will be asked to log in to RZS NSW). Do not log in at the top of this current page for access.
Citing articles via
Professional kangaroo population control leads to better animal welfare, conservation outcomes and avoids waste
George R Wilson, Melanie Edwards