Effect of dietary lipid on fatty acid composition of the muscle of reared Tunisian greater amberjack Seriola dumerili

Gam Haouas W., Guerbej H., Zayene N., Hammami M., Achour L.

Date de parution: juin 2010
Volume: 34
Number: 2
Pagination: 151–158
Résumé

The greater amberjack Seriola dumerili (Risso, 1810) is one of the most commercially important seawater fish species in Tunisia. The aim of this study was to determine the best rate of dietary lipid for Seriola dumerili during the refining period and its effect on muscle fatty acid composition. Two groups of fish were fed for 8 weeks with commercial diets with increasing lipid levels (45% crude protein, 17 or 25% lipid). The fat content and fatty acid composition of edible muscle were investigated. The lipid content increased with increasing dietary lipid levels. Fatty acid (FA) composition of the muscle reflected dietary FA profiles. Along the experiment, polyunsaturated fatty acid (PUFA) levels of Seriola dumerili were found to be higher than those of saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) for the two diets tested. The proportions of n-3 PUFAs of Seriola dumerili (ranging from 19.24 ± 0.98% to 29.15 ± 0.49% and 33.89 ± 0.94% for fish fed the 17% fat diet and the 25% fat diet, respectively) were higher than those of n-6 PUFAs. Docosahexaenoic acid (DHA 22:6 n-3), eicosapentaenoic acid (EPA 20:5 n-3) and arachidonic acid (AA 20:4 n-6) were the main PUFA. Farmed Seriola dumerili was characterised by a higher n-3/n-6 ratio in different samples studied and diet tested, but the best ratio was observed with the lipid rich diet at 45 days of refining. Greater amberjack provides the consumer with a high proportion of n-3 FA, particularly DHA and EPA

Mots-clés: Carangidae - Dietary lipid - Fatty acids - n-3/n-6 ratio - PUFA - Seriola dumerili
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