Comparison of fatty acid contents of wild and cultured rainbow trout Onchorhynchus mykiss in Turkey

Abstract

The total lipid content and fatty acid composition were determined in the flesh and skin of wild and cultured rainbow trout in Turkey. The effect of diet content was also investigated on cultured trout. Gas chromatography-mass spectrometry (GC-MS) was used for fatty acid analyses. Total lipid content of skin was higher than flesh in both types and when compared appreciably higher in cultured fish. The predominant fatty acid was palmitic acid (C16∶0) in saturated fatty acids and oleic acid (C18∶1n−9) in monounsaturated fatty acids. The amount of eicosapentaenoic acid was double in wild and docosahexaenoic acid (DHA) 1.5 times higher in cultured fish flesh. The n−3/n−6 ratio was higher in cultured fish than wild fish. The levels of palmitic, oleic, linoleic (C18∶2n−6) and palmitoleic (C16∶1n−7) acids were high in skin. The level of EPA was the same in skin of wild fish but 5.5 times higher in cultured fish, where as the proportion of DHA in skin was lower for wild and 3.5 times higher in cultured fish. Wild fish had a high level of linoleic, arachidonic (C20∶4n−6) and linolenic (C18∶3n−3) acids. The total amount of n−3 and n−6 polyunsaturated fatty acids was higher in flesh of wild fish than cultured fish, contrary to skin of cultured fish. The data obtained demonstrated that fatty acid composition of cultured fish did not depend on that of feed.