Title

Seasonal Differences In Biochemical Adaptation To Fasting In Juvenile And Subadult Steller Sea Lions (Eumetopias Jubatus)

Abstract

Nine Steller sea lions (Eumetopias jubatus) aged 1.75-6 yr were experimentally fasted for 7-14 d during the breeding and non- breeding seasons to identify changes in plasma metabolites that are indicative of fasting and to determine whether the ability of sea lions to fast varies seasonally or with age. Although some animals approached the limit of their protein-sparing ability by the end of our fasting experiments, there was no sign of irreversible starvation biochemistry. Plasma blood urea nitrogen (BUN) concentrations decreased in all animals within the first week of fasting, reflecting a shift to a fasting-adapted state; however, significant increases in plasma BUN concentration at the end of the nonbreeding season fasts suggest that subadult Steller sea lions were not able to maintain a protein-sparing metabolism for a full 14 d during the nonbreeding season. In contrast, juveniles were able to enter protein sparing sooner during the nonbreeding season when they had slightly higher initial percent total body lipid stores than during the breeding season. Subadult and juvenile sea lions had low circulating ketone body concentrations compared with young sea lion pups, suggesting an age-related difference in how body reserves are utilized during fasting or how the resulting metabolites are circulated and catabolized. Our data suggest that metabolite concentrations from a single blood sample cannot be used to © 2009 by The University of Chicago.

Publication Date

5-1-2009

Publication Title

Physiological and Biochemical Zoology

Volume

82

Issue

3

Number of Pages

236-247

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1086/597528

Socpus ID

67149086774 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/67149086774

This document is currently not available here.

Share

COinS