Effect of different concentration of linseed oil in the diets on content of essential fatty acids of common carp, Cyprinus carpio, L

Abstract

Common carp fingerlings were fed five diets in triplicate containing 0, 2, 3, 4 and 5% linseed oil for 75 days to determine effect of different concentration of LO on chemical and fatty acid composition of fish. Fish, average initial weight 200± 4 g, were stocked in 15 cages. Fish fed the 3, 4 and 5% LO diets had significantly better growth parameters compared to fish fed the 0 or 2% LO diets. Lipid content in muscle increased from 1.25% in the 0% LO, to 1.46%; 1.56 %; 1.94% and 2.37% in the 2, 3, 4 and 5% LO treatments, respectively. Fatty acid profiles in muscle tissue reflected the diet concentrations with significant increases (p <0,01) in 18:3n-3 in fish fed the 2, 3, 4 and 5% LO diets. Other fatty acids showing significant (p <0,01) muscle concentration increases in fish fed the LO diets were: C20:3n-3, C20:5n-3, C22:5n-3, C22:6n-3, as well as polyunsaturated fatty acids (PUFA), total n-3 fatty acids, and the n-3/n-6 ratio. Fatty acids which showed significant decreases (p<0,01) were saturated fatty acids (SFA). Fish fed the 5% LO diets had twice much n-3 fatty acids (7.05%) than those without LO (2.65%). N-3/n6 ranged from 0.14 in fish fed without LO to 0.33 in fish fed 5%LO. Inclusion of 5% LO in diets showed the most favourable effects on content of essential fatty acids in tissue of carp as well as on other tested parameters.