Food and oxygen requirements for growing mice and turtles after hypergravitational development.
Although development of mice and turtles, both low-payload animals, can be influenced by ambient gravitational intensity, little is known regarding the influence of either their growth or their gravitational history upon life-support requirements. A 25-g male Box Turtle (Terrapene carolina, optimally growing at 30 degrees C and 1 G to double its size in 7 weeks) exhibits daily requirements of oxygen (100 ml) and food (200 mg, dry) which are only 3% of the requirement for a mouse (Swiss Webster, centrifuged at 22 degrees) of comparable size and growth rate. These requirements grow in proportion to the turtle's (body mass)0.9 and to the mouse's (body mass)0.5. After development at hypergravity g (of from 1.5 to 5 G expressed in multiples of the earth's gravity) there is a one-day delay for turtles but an immediate change for mice in these requirements upon return to 1 G. Although both show a decreased oxygen intake, the drop is greater for turtles (equalling g -0.4 of the baseline value, as corrected for body size, after return from 75 days exposure against g-0.08 for mice after 1-13 days exposure); the food intake drops for turtles (varies as g-1) while it rises for mice (varies as g0.6).
Wunder
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Department of Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA.
Dodge
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Cook
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Moressi
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D000818:Animals; D001835:Body Weight; D002498:Centrifugation; D004032:Diet; D004435:Eating; D018471:Hypergravity; D008021:Life Support Systems; D051379:Mice / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology*; D014426:Turtles / Q000502:physiology*