Seasonal variations in the fatty acid composition of phospholipids and triacylglycerols of brown trout

Abstract

Seasonal variations on phospholipid (PL) and triacylglycerol (TG) fatty acid (FA) compositions in muscles of Salmo trutta macrostigma were investigated by gas chromatography (GC) using the method described by Folch. The total lipid of the muscle was extracted using chloroform/methanol (2:1, v/v) and was separated into TG and PL using thin layer chromatography (TLC). A total of nineteen and sixteen different fatty acids were determined in TG and PL, respectively. The distributions of ΣSFAs (saturated fatty acids), ΣMUFAs (monounsaturated fatty acids) and ΣPUFAs (polyunsaturated fatty acids) proportions were found to be different among PL and TG fractions in all seasons. TG contained a lower proportion of ΣPUFA, but a higher proportion of ΣMUFA and ΣSFA than PL. The major components were palmitic acid (16:0), oleic acid (18:1 n‐9), eicosapentaenoic acid (EPA, 20:5 n‐3) and docosahexaenoic acid (DHA, 22:6 n‐3) in PL, 16:0, palmitoleic acid (16:1 n‐7), 18:1 n‐9, linoleic acid (LA, 18:2 n‐6), linolenic acid (ALA, 18:3 n‐3), 20:5 n‐3 and 22:6 n‐3 in TG extracted from muscle of S. trutta macrostigma in all seasons. The total lipid content varied seasonally from 1.44% to 1.90% in female muscle of wet weight for S. trutta macrostigma . N‐3/n‐6 ratios of PL and TG were found to be 5.19–12.0 and 1.09–2.62, respectively. Practical applications: The information in this study will be of practical value from a health perspective for populations who consume S. trutta macrostigma and for food producers. Effect of seasonal variations on the fatty acid compositions of phospholipid and triacylglycerol fractions of Salmo trutta macrostigma were investigated in view of saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids by using GC.