Effects of Environmental Salinity on Lipid Classes and Fatty Acid Composition in Gills of Atlantic Salmon

Abstract

Atlantic salmon Salmo salar were kept in water with different NaCl concentration (salinity: 0, 1 and 2%) for 48 h in order to determine the effects of environmental salinity on lipid classes and their fatty acid composition of gills. The percentage of gill weight to body weight decreased in fish kept in water with 1 and 2% salinity for 24 h. The total lipid of gills (mg/100 g fish body weight) also decreased from 897 mg of the initial value to 727 and 747 mg after adaptation to 1 or 2% salt water for 24 h. This was mainly due to decrease of triglyceride class of gill lipids. On the other hand, the content of polar lipids such as phosphatidylcholine (PC) and phosphatidylethanolamine (PE) was not influenced by salinity levels during 48 h adaptation. The adaptation of salmon to 1 or 2% salt water for 24 h remarkably reduced the level of n-3 highly unsaturated fatty acids, especially docosahexaenoic acid (DHA) of PC in gill, while no change was observed in fatty acids of PE. On the other hand, all fatty acids in gill nonpolar lipids were decreased. These results suggest that some selected fatty acids such as DHA in gill polar lipids may have an important role for salinity adaptation. © 1989, The Japanese Society of Fisheries Science. All rights reserved.