Fatty Acid Profile of Muscles of Freshwater Fish from Olsztyn Markets

The aim of the present study was to determine the profile of fatty acids in muscle lipids of freshwater fish: carp (Cyprinus carpio L.), rainbow trout (Oncorhynchus mykiss Walb.), bream (Abramis brama L.) and tench (Tinca tinca L.) from markets of Olsztyn (north-eastern Poland). Separation and identification of fatty acids were made using gas chromatography. The content of some fatty acids varied among species. Generally, palmitic acid (15.6%-19.5%) was the most abundant saturated fatty acid (SFA). The main monounsaturated fatty acid (MUFA) was oleic acid (20.7%-42.7%). Linoleic (4.6%-8.0%), arachidonic (AA) (0.8%-6.6%), docosahexaenoic (DHA) (1.7%-15.9%) and eicosapentaenoic (EPA) (1.2%-8.8%) acids were the predominant polyunsaturated fatty acids (PUFA). There were no significant differences (p>0.05) in the content of SFA (24.3%-28.7%) among the fish species. The content of MUFA in muscle lipids of carp (55.0%) was significantly higher (p≤0.01) than in the lipids of the other fish examined (35.8%-38.3%). Bream and rainbow trout (26.6% and 27.7%, respectively) contained significant more n-3 PUFA than carp (4.7%) and tench (20.5%) (p≤0.01). Total n-6 PUFA ranged between 8.4% (rainbow trout) and 12.9% (tench). Significant differences in n-6 PUFA content were only observed in the case of these fish (p≤0.01). The differences in the n-3/n-6 ratio (rainbow trout (3.3) > bream (2.6) > tench (1.6) > carp (0.4)) were statistically significant (p≤0.01).