Title

Utilization Of Stored Energy Reserves During Fasting Varies By Age And Season In Steller Sea Lions

Abstract

Nine captive Steller sea lions (Eumetopias jubatus (Schreber, 1776), 1.75-6 years of age) were fasted for 7-14 d to test the effect of short-term fasting on changes in body mass and body condition. Trials were repeated during both the summer breeding season and the nonbreeding season in seven animals to elucidate whether there was a seasonal component to the ability of Steller sea lions to adapt to limited food resources. Mean percent mass loss per day was higher during the breeding season in juveniles (1.8% ± 0.2%·d -1) than in subadults (1.2% ± 0.1%·d-1), but there were no significant age-related differences during the nonbreeding season (juveniles, 1.5% ± 0.3%·d-1; subadults, 1.7% ± 0.3%·d-1). A decrease in the rate of mass loss occurred after the first 3 d of fasting only in subadults during the breeding season. Percent total body lipid ranged from 11% to 28% of total body mass at the initiation of fasting trials. Animals with lower initial percent total body lipid exhibited higher subsequent rates of mass loss and a lower percentage of tissue catabolism derived from lipid reserves. There was no evidence of metabolic adaptation to fasting in juveniles, which suggests that juvenile sea lions would be more negatively impacted by food limitation during the breeding season than would subadults. © 2007 NRC.

Publication Date

2-1-2007

Publication Title

Canadian Journal of Zoology

Volume

85

Issue

2

Number of Pages

190-200

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1139/Z06-204

Socpus ID

34347235426 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/34347235426

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