Caviar
composition in wild and cultured sturgeons - impact of food sources on fatty
acid composition and contaminant load
J. Gessner, M. Wirth, F. Kirschbaum, A. Krüger,
N. Patriche-2002
Journal of
Applied Ichthyology, 18(4-6): 665-672
Abstract:
Caviar production from aquaculture is
increasing whereas fishery yields are in decline. It is therefore of
interest to identify the differences in caviar of various origins. In
particular, the question arises whether the composition of caviar is
attributable to feeding and processing practices. Egg size, protein and fat
content are not applicable for species discrimination. Gross composition of
the end-product largely depends on the salt content and thereby is
influenced by the processing technology. According to our results, the
composition of sturgeon caviar from intensive aquaculture varies to a large
extent from that of wild origin. Fatty acid composition in extensively
reared sturgeon did not differ largely from that of wild-caught fish. As the
difference is only apparent between fish reared on formulated diets and
wild-caught fish, the applicability of this tool for product source
determination is restricted. Cadmium and lead are not enriched in the eggs.
The elevated levels detected for copper and zinc reflect the requirements of
the fish. The amount of chlorinated hydrocarbons (
DDT,
PCB,
HCH)
varied over a wide range, revealing typical differences related to origin,
source and species. Based on the observed differences between caviar from
wild and intensively farmed fish, development of a diet is necessary to
coincide with the requirement of sturgeons. The study suggests altering the
fatty acid composition by reducing the linoleic (18 : 2) acid
content while increasing the arachidonic (20 : 4) acid to match
the caviar composition in wild-caught sturgeons. This also is expected to
improve growth and reproduction in sturgeons raised in captivity.
(Leibnitz Institute of Freshwater Ecology
and Inland Fishery, PO Box 850123, D-12651 Berlin, Germany. E-mail: sturgeon@igb-berlin.de)
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