Utilization of stored energy reserves during fasting varies by age and season in Steller sea lions

    Authors

    L. D. Rea; D. A. S. Rosen;A. W. Trites

    Comments

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    Abbreviated Journal Title

    Can. J. Zool.-Rev. Can. Zool.

    Keywords

    HYDROGEN-ISOTOPE-DILUTION; MIROUNGA-ANGUSTIROSTRIS PUPS; ARCTOCEPHALUS-GAZELLA PUPS; BODY-COMPOSITION CHANGES; EUMETOPIAS-JUBATUS; FUR SEALS; PROTEIN CATABOLISM; METABOLIC-RATE; HARBOR SEALS; CALLORHINUS-URSINUS; Zoology

    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%center dot d(-1)) than in subadults (1.2% +/- 0.1%center dot d(-1)), but there were no significant age-related differences during the nonbreeding season (juveniles, 1.5% +/- 0.3%center dot d(-1); subadults, 1.7% +/- 0.3%center dot 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.

    Journal Title

    Canadian Journal of Zoology-Revue Canadienne De Zoologie

    Volume

    85

    Issue/Number

    2

    Publication Date

    1-1-2007

    Document Type

    Article

    Language

    English

    First Page

    190

    Last Page

    200

    WOS Identifier

    WOS:000245590000006

    ISSN

    0008-4301

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