Comparative study of
antioxidant defence mechanisms in marine fish fed variable levels of
oxidised oil and vitamin E
D.R. Tocher, G. Mourente, A. Van der Eecken, J.O. Evjemo, E.
Diaz, M. Wille, J.G. Bell, Y. Olsen-2003
Aquaculture
International, 11
(1-2): 195-216
Abstract:
The aim of the study was to compare the antioxidant
systems in juvenile marine fish of commercial importance to European
aquaculture, namely turbot (Scophthalmus maximus), halibut (Hippoglossus
hippoglossus) and gilthead sea bream (Sparus aurata). The
present dietary trial was specifically designed to investigate the
antioxidant effects of vitamin E under moderate oxidising conditions,
including high dietary levels of highly unsaturated fatty acids and the
feeding of oxidised oils. The objective was to induce a stressful
pro-oxidant status to enable characterisation of the biochemical responses
to peroxidative stress without causing unnecessary suffering to the
experimental animals or high mortalities during the trials. Both sea bream
and turbot showed excellent growth, whereas growth was poorer in halibut.
Dietary oxidised oil significantly reduced growth in turbot and especially
in halibut, but not in sea bream. Vitamin E improved growth in sea bream fed
oxidised oil but not in turbot or halibut. However, vitamin E
supplementation appeared to improve survival in all three species. In sea
bream and turbot, liver antioxidant defence enzyme activities were generally
increased by feeding peroxidised oil and reduced by vitamin E. Conversely,
in halibut, the liver antioxidant defence enzyme activities were not
increased by feeding peroxidised oil and only superoxide dismutase was
reduced by feeding vitamin E. Consistent with these data, feeding oxidised
oil increased lipid peroxidation products in halibut, but generally not in
sea bream or turbot. Furthermore, lipid peroxidation products were generally
reduced by dietary vitamin E in both sea bream and turbot, but not in
halibut. Therefore, halibut liver antioxidant defence enzymes did not
respond to dietary oxidised oil or vitamin E as occurred in turbot and,
especially sea bream. This resulted in increased levels of lipid peroxides
in halibut compared to turbot and sea bream in fish given dietary oxidised
oil. In addition, supplemental vitamin E did not reduce lipid peroxides in
halibut as it did in turbot and sea bream. The increased peroxidation stress
in halibut may account for their poorer growth and survival in comparison to
turbot and especially sea bream. Halibut were reared at a lower temperature,
although relatively high for halibut, than either turbot or sea bream but
they were also slightly younger/smaller fish and possibly, therefore, more
developmentally immature, and either or all of these factors may be
important in the lack of response of the liver enzymes in halibut.
(Institute of
Aquaculture, University of Stirling, Stirling FK9 4LA, Scotland, UK)