Seasonal changes in fatty acid composition and fat soluble vitamins content of grass carp and common carp

Abstract. The aim of the present study is to evaluate the seasonal changes in total lipids and fatty acid (FA) composition, and fat soluble vitamins (A, D3, E) content in the edible tissue of two freshwater fish species – grass carp and common carp. The FA and vitamins contents of the investigated fish species showed significant seasonal changes. All spring samples were characterized by lower saturated fatty acid (SFA) levels (from 35.9% to 36.0%) and higher polyunsaturated fatty acids (PUFA) (from 14.6% up to 30.1%), including the essential omega 3 PUFA compared to the autumn specimens. The autumn carp and grass carp showed significant decrease of the monounsaturated fatty acids (MUFA) levels. All autumn samples showed lower PUFA (from 13.3% to 30.0%) values, due to reduction of linoleic acid (C 18:2 n6) levels in carp and grass carp. PUFA/SFA and n-3/n-6 ratios decreased in all fish species in the autumn season. The fat soluble vitamins content of the analyzed species in the two seasons were in the ranges: from 8.56±0.68μg/100g to 24.44±5.8 μg.100g-1 wet weight (ww) for all-trans-retinol; from 5.41±0.33 μg.100g-1ww to 30.87±5.1 μg.100g-1ww cholecalciferol and from 1051.8±38.470 μg.100g-1ww to 3133.1± 57.8 μg.100g-1ww α-tocopherol, respectively. All analyzed cyprinid species in both seasons are good sources of fat soluble vitamins and PUFAs, which makes them a desirable part of the human diet.