Comparison of fatty acid composition in some tissues of rainbow trout (Oncorhynchus mykiss) living in seawater and freshwater

The effects of salinity on the fatty acid profiles of liver, gonad, muscle and adipose tissues of rainbow trout (Oncorhynchus mykiss) kept in cages suspended in a seawater (SW) and freshwater (FW), respectively, and fed with the same commercially available diets before marketing, were investigated. In muscle tissue, the effect of salinity (0.17%) was found to be insignificant in terms of the total monounsaturated fatty acid (MUFA), total polyunsaturated fatty acid (n-3, n-6 PUFA) and total saturated fatty acid (SFA), but significant in terms of the eicosapentaenoic acid (EPA)/docosahexaenoic acid (DHA) ratio. In gonad and liver tissues, MUFA and n-3 PUFA were found to be significantly affected by salinity, but not SFA or n-6 PUFA. In adipose tissues, all the parameters were significantly affected by salinity. Also n-3/n-6 PUFA and EPA/DHA ratios were characteristic for FW and SW fish. While the salinity significantly affected the n-3/n-6 ratio in the adipose and liver tissues, it did not have any significant effect in the muscle and gonads. Additionally, the EPA/DHA ratio was found to be significantly affected by the salinity in all the tissues examined. (C) 2003 Elsevier Ltd. All rights reserved.