Cardiac performance in relation to oxygen supply varies with
dietary lipid composition in sturgeon.
Agnisola, C., D. J. McKenzie, E. W. Taylor, C. L. Bolis, and B. Tota.
Department of General and Environmental Physiology, University of
Naples "Federico II", via Mezzocannone 8, 80134 Naples,
Italy; School of Biological Sciences, University of Birmingham,
Birmingham, B15 2TT, United Kingdom; Institute of Pharmacological
Sciences, University of Milan, via Balzaretti 9, 20133 Milan, Italy;
Department of Cell Biology, University of Calabria, 87030 Arcavacata
di Rende (CS), Italy and "A. Dohrn" Zoological Station, Villa
Comunale, 80121 Naples, Italy
APStracts 3:0068R, 1996.
Dietary polyunsaturated fatty acids (PUFA) of the n-3 series that have
beneficial effects on mammalian heart function are typically found at
high levels in fish tissues. The effects of dietary fatty acid
composition on cardiac function were investigated in the sturgeon.
When compared with sturgeon maintained for one year on a diet
enriched with saturated fatty acids (SFA) (the coconut oil
supplemented diet, COD), sturgeon maintained on a diet enriched with
n-3 PUFA (the fish oil supplemented diet, FOD) had higher myocardial
20:5 n-3 and lower 20:4 n-6 content with a consequent decrease in the
n-6 to n-3 ratio (from 0.86 to 0.25), a lower intrinsic in vitro
heart rate (22.0 1.5 versus 29.9 1.0 beats min-1) and cardiac power
output (PO) (0.33 0.08 versus 0.48 0.03 mW g-1) but had a greater in
vitro scope for cardiac work (almost twice the maximal to basal PO
ratio). Reducing the oxygen supply to the hearts significantly
decreased, by about 40%, the maximal in vitro power output in the COD
group of animals but had no effect in the FOD group. These
differences in performance were not reflected in heart rate or blood
pressure in vivo, either in normoxia or hypoxia. Addition of vitamin
E, as an antioxidant, to the diets, reduced intrinsic heart rate by
about 25% but did not influence the effects of dietary fatty acid
composition on in vitro cardiac performance. The results indicate
that dietary n-3 PUFA can have beneficial effects on the resistance
of the fish heart to environmental stressors such as hypoxia.
Received 28 June 1995; accepted in final form 20 February 1996.
APS Manuscript Number R408-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 13 March 96