Fasting metbabolism in Antarctic fur seal (Artocephalus gazella) pups

Arnould, John, Green, J.A. and Rawlins, D.R. 2001, Fasting metbabolism in Antarctic fur seal (Artocephalus gazella) pups, Comparative biochemistry and physiology. Part A, Molecular & integrative physiology, vol. 129, no. 4, pp. 829-841.


Title Fasting metbabolism in Antarctic fur seal (Artocephalus gazella) pups
Formatted title Fasting metabolism in Antarctic fur seal (Artocephalus gazella) pups
Author(s) Arnould, John
Green, J.A.
Rawlins, D.R.
Journal name Comparative biochemistry and physiology. Part A, Molecular & integrative physiology
Volume number 129
Issue number 4
Start page 829
End page 841
Publisher Elsevier Science
Place of publication New York, N.Y.
Publication date 2001-07
ISSN 1095-6433
Keyword(s) otariid
pinnipeds
fasting metabolism
RMR
ketone bodies
plasma metabolites
protein catabolism
neonates
Summary The metabolism of 52–73-day old Antarctic fur seal pups from Bird Island, South Georgia, was investigated during fasting periods of normal duration while their mothers were at sea foraging. Body mass decreased exponentially with pups losing 3.5–3.8% of body mass per day. Resting metabolic rate also decreased exponentially from 172–197 ml (O2)·min−1 at the beginning of the fast and scaled to Mb0.74 at 2.3 times the level predicted for adult terrestrial mammals of similar size. While there was no significant sex difference in RMR, female pups had significantly higher (F1,18=6.614, P<0.019) mass-specific RMR than male pups throughout the fasting period. Fasting FMR was also significantly (t15=2.37, P<0.035) greater in females (823 kJ·kg−1·d−1) than males (686 kJ·kg−1·d−1). Average protein turnover during the study period was 19.3 g·d−1 and contributed to 5.4% of total energy expenditure, indicating the adoption of a protein-sparing strategy with a reliance on primarily lipid catabolism for metabolic energy. This is supported by observed decreases in plasma BUN, U/C, glucose and triglyceride concentrations, and an increase in β-HBA concentration, indicating that Antarctic fur seals pups adopt this strategy within 2–3 days of fasting. Mean RQ also decreased from 0.77 to 0.72 within 3 days of fasting, further supporting a rapid commencement of protein-sparing. However, RQ gradually increased thereafter to 0.77, suggesting a resumption of protein catabolism which was not substantiated by changes in plasma metabolites. Female pups had higher TBL (%) than males for any given mass, which is consistent with previous findings in this and other fur seal species, and suggests sex differences in metabolic fuel use. The observed changes in plasma metabolites and protein turnover, however, do not support this.
Language eng
Field of Research 060603 Animal Physiology - Systems
HERDC Research category C1.1 Refereed article in a scholarly journal
Copyright notice ©2001, Elsevier Science Inc.
Persistent URL http://hdl.handle.net/10536/DRO/DU:30015950

Document type: Journal Article
Collection: School of Life and Environmental Sciences
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