Fatty acid profiles in marine and freshwater fish from fish markets in northeastern Poland

The fatty acid compositions were studied in eight commercially important fish from fish markets: salmon, Salmo salar L.; cod, Gadus morhua L.; common sole, Solea solea (L.); European flounder, Platichthys flesus (L.); catfish, Clarias gariepinus (Burchell); rainbow trout, Oncorhynchus mykiss (Walb.); Nile tilapia, Oreochromis niloticus (L.); and pangasius, Pangasianodon hypophthalmus (Sauvage). The freshwater fish contained 25.69-42.18% saturated, 34.90-43.79% monounsaturated, 8.46-16.32% n-6 polyunsaturated, and 5.01-20.43% n-3 polyunsaturated acid, while marine fish contained 18.53-32.77% saturated, 17.95-49.89% monounsaturated, 3.40-11.51% n-6 polyunsaturated, and 18.74-45.42% n-3 polyunsaturated acid. Marine fish contained significantly more Ʃn-3 PUFA (29.79%), EPA (12.26%), DHA (13.20%), and a higher n-3/n-6 (6.95) ratio than freshwater fish (13.13, 2.47, 7.14, 1.29%) (P≤ 0.05). There were statistically significant differences in the n-3/n-6 ratio among fish species (cod (13.40) > sole (8.47) > flounder (4.30) > rainbow trout (2.41) > catfish (1.83) ≈ salmon (1.63) > tilapia (0.57) ≈ pangasius (0.36) (P ≤0.05)).