FATTY-ACID COMPOSITION OF ENDEMIC BAIKAL FISH AND CRUSTACEA

1. A study was made of the fatty acid composition of polar and neutral lipids in liver, gonads and red and white muscles of two endemic Baikal fish species: Cottocomephorus grewingki and Cottocomephorus inermis and of the Crustacea Epishura baicalensis and Macrohectopus branickii. 2. We have detected a high level of polyunsaturated (n-3) series fatty acids, unusual for freshwater fish. According to the fatty acid ratio (n-3)/(n-6) in polar lipids, the Baikal fish occupy an intermediate place between freshwater and marine fishes and, in regard to neutral lipids, they refer to typically freshwater species. 3. It is shown that 22:6(n-3), 16:0, 18:1 are the main components of fatty acids of these fish and Crustacea and, among them, 22:6(n-3) is dominant. 4. In the spawning period, in comparison with that of sexual maturation, the 22:6(n-3) content of polar lipids decreases in the liver; the content of 16:1 decreases in neutral lipids and the content of C18 of polyunsaturated fatty acids increases in the liver and red muscles in both species. 5. The fish C. grewingki and C. inermis have an identical fatty acid composition, although their foods differ in fatty acid composition.