High lipid content enhances the rate of oxygen diffusion through
fish skeletal muscle.
Desaulniers, Nicole, Timothy S. Moerland, and Bruce D. Sidell.
Department of Zoology and Center for Marine Studies, University of
Maine, 5751 Murray Hall, Orono, ME 04469-5751, Department of
Biological Sciences, Florida State University, Biology Unit I,
Tallahassee, FL 32306-3050, Current address: Marine Science
Institute, University of California at Santa Barbara, Santa Barbara,
CA 93106-6150
APStracts 3:0038R, 1996.
The diffusion coefficient for oxygen (DO2) and the solubility constant
for oxygen ([alpha]O2) were measured at 15 degrees C in oxidative
muscle from striped bass (Morone saxatilis) that had been acclimated
to 5 degrees and 25 degrees C. This design allowed us to test the
hypothesis that changes in composition of the tissue that are known
to occur during thermal acclimation may affect oxygen movement. Our
measurements permitted calculation of the diffusion constant for
oxygen (KO2) through the tissue, which is a primary determinant of
capacity for oxygen flux. Under isothermal conditions, [alpha]O2 [ml
O2 (cm3 x atm)-1] was (3.59 +/- 0.20)X10-2 and (6.64 +/- 0.27)X10-2
in tissues from 25 degrees - and 5 degrees C-acclimated animals,
respectively. Because oxygen is more soluble in lipid than aqueous
phase, higher [alpha]O2 in tissues from cold-acclimated animals can
be accounted for by the 13-fold increase in lipid content that is
known to occur in oxidative muscle of striped bass during acclimation
from 25 degrees to 5 degrees C. When measured under similar
isothermal conditions, DO2 showed no significant difference between
animals acclimated to warm or cold temperature; DO2 [cm2 x sec-1]
through tissues from 25 degrees - and 5 degrees C-acclimated animals
was 2.50 +/- 0.18 and 2.57 +/- 0.40, respectively. Because [alpha]O2
increases, the calculated diffusion constant for oxygen (KO2 = DO2 x
[alpha]O2) is greater in tissue from cold- than from warm-acclimated
fish. At physiological temperature, elevated lipid content in
oxidative muscle of cold-acclimated striped bass should result in
enhanced intracellular movement of oxygen and at least partially
offset the expected decrease in DO2 at cold temperature.
Received 10 March 1995; accepted in final form 16 January 1996.
APS Manuscript Number R160-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 8 February 96