Fatty acid profiles in different fish species in Lake Baikal

The fatty acid (FA) composition in the heart tissue and white muscle of 13 species/ecoforms of Lake Baikal fish was determined. All the FAs usually found in freshwater or marine fish were detected in both tissues of all species studied. White muscle con- tained lower levels of saturated and monounsatu- rated FAs (SAFAs and MUFAs), and higher levels of poly unsaturated FAs (PUFAs) than heart tissue. The n3/n6 PUFA ratio ranged between 1.3 and 3.2 in heart tissue and 1.4 and 6.6 in white muscle, typical for fresh- water fish. The most prominent n3 PUFAs, 20:5n3 and 22:6n3, occurred at levels comparable to those found in corresponding species in other freshwater lakes and rivers and also in marine fish. The FA compositions were species specific, following the taxonomic distinc- tion between the species. Apparently, dietary FAs are modified significantly through the metabolism of the fish to produce the species-specific FA composition necessary for the structural lipids of heart tissue and white muscle.