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  • UC Riverside
  • College of Natural and Agricultural Sciences

Publications: Mark Chappell

Janes DN, Chappell MA (1995) The effect of ration size and body size on specific dynamic action in Adélie penguin chicks, Pygoscelis adeliae. Physiological Zoology 68:1029-1044.

ABSTRACT -- Specific dynamic action (SDA), also termed the heat increment of feeding, is defined as the postprandial increase in O2 consumption. The physiological cause of SDA is poorly understood, but most studies point to energetic expenditures associated with protein synthesis. Although SDA has been quantified in many different animal taxa, it has been seldom measured in birds. The purpose of this study was to measure SDA in Adélie penguin chicks, and to examine possible changes in SDA parameters during growth. Adélie penguin chicks of all sizes exhibited substantial SDA that increased with the size of the meal. The SDA coefficient was 10.0% of ingested energy, and 14.8% of metabolizable energy. These values did not vary with body mass. Postprandial peak oxygen consumption rates did not vary with meal size. The time course of SDA increased with the ration level but did not vary with either body mass or meal size alone. Our estimate of the cost of growth in penguin chicks is intermediate between costs measured for other organisms. SDA may serve a functional role in thermoregulation for Adélie penguins, which routinely experience temperatures below thermoneutrality. Cumulative SDA during growth is equal to about 62% of the energy deposited in new tissue.