Fatty acid composition of total lipid, phospholipid and triacylglycerol in the gonad and liver tissue of Carasobarbus luteus.

Abstract

AlM OFTHE STUDY: Fatty acids, especially fish lipids, are important nutritional elements for human health. The beneficial effect of fish consumption on human health has been related, among other factors, to the high content of n-3 fatty acids, especially EPA and DHA, which play an important role in the prevention of a wide variety of disorders, such as atherosclerosis, thrombosis, hypertension, autoimmune and inflammatory diseases, rheumatoid arthritis, osteoporosis, breast cancer asthma and allergy. There has been no study on the fatty acid profiles of phospholipid and triacylglycerol from Carasobarbus luteus. Therefore, the objectives of the present work were to investigate the total lipid contents and fatty acid profiles in the gonad and liver of C. luteus. MATERIAL AND METHODS: Fishes were caught with casting nets from Atatürk Dam Lake on May 2008. Fish were killed with a sharp blow to the head; gonad and liver were excised. Fish sex was determined by their gonad. The samples were stored at -30 oC in a freezer prior to analysis. LIPID EXTRACTION AND TRANSMETHLATION OF FATTY ACIDS Gonad and liver tissues were homogenised in chloroform/methanol (2 /1, v /v) solution in order to extract gonad and liver tissue lipids. The amount of lipid was determined gravimetrically. Then the total lipids were spotted on preparative thin layer chromatography (TLC) plates using commercial silica gel TLC plates. After applying the lipid extracts, the TLC plates were developed in petroleum ether: diethyl ether: acetic acid (80:20:1 v/v). The fractions were scraped into reaction vials, and the associated fatty acids were transmethylated by refluxing the fractions in acidified methanol for 2 hours at 85 OC. The fatty acid methyl esters were extracted with hexane. Fatty acid methyl esters were separated and quantified by capillary gas chromatography (GC) using a Hewlett Packard GC, a flame ionization detector (FID] and Hewlett-Packard ChemStation software. Statistical analyses were done with SPSS 15.0. RESULTS: The major SFAs (saturated fatty acids) were palmitic acid (C16:0) and stearic acid (C18:0). Oleic acid (C18:1n-9) and palmitoleic acid (C16:1n-7) were the prominent MUFA (monounsaturated fatty acids). The dominant PUFAs (polyunsaturated fatty acids) were arachidonic acid (AA, C20:4n-6), eicoesapentaenoic acid (EPA, C20:5n-3] and docoesahexaenoic acid [DHA, C22:6n-3] in both tissues. The distributions of SFAS, MUFAs and PUFAs proportions were found to be different among PL and TAG fractions. TAG contained a lower proportion of PUFA, but a higher proportion of MUFA and SFA than PL.