Composition of muscle tissue lipids of silver carp and bighead carp

Lipids have a complex role in the nutritional value of food. Some polyunsat urated fatty acids, characterized as essential, are extremely important for human health. This is primarily related to alpha-linolenic acid (18:3n-3), eicosapentaenoic acid (20:5n-3) and docosahexaenoic acid (22:6n-3). Conten t of polyunsaturated n-3 fatty acids is usually much higher in lipids of ma rine fish than in freshwater fish. Previous investigations have shown that muscle tissue of silver carp and bighead carp from fish farms may be a rich source of essential fatty acids. Because of that, the objective of this wo rk was to examine contents and composition of fatty acids and total lipids in the muscle tissue of silver and bighead carp, with the aim to find out w hether there are significant differences in this respect between the two sp ecies and to what extent the harvest season can influence the composition o f lipids in these freshwater fish. This study showed that there is no signi ficant difference either in the content of polyunsaturated n-3 and n-6 fatt y acids, or in the n-6/n-3 fatty acid ratio in these two fish species. The lipids of both the silver and bighead carp from the spring harvest have sig nificantly higher contents of the n-3 acids and a significantly lower n-6/n -3 ratio than fish from the autumn harvest.