Fatty acid composition in salmonid eggs : a comparative study of Atlantic salmon and brown trout

Abstract: Atlantic salmon (AS) and brown trout (BT) are part of the salmonid family and are some of the most popular fish species in Western culture. Due to their popularity, there is incentive to understand the varying factors which ensures species survival. This paper aims to investigate the varying roles and relationships of the salmonid eggs fatty acids (FA). Its purpose is to investigate and compare the fatty acid (FA) composition of fertilized eggs from AS and BT spawning in the Dala river and relate the results to egg quality, as well as compare the results to findings in a study from 1998. Specific emphasis is on the important FA arachidonic acid (AA), docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) as these FA are linked to healthy embryonic development. The FA composition of the two species were quite similar and mainly differed in the specific FA distribution between the triacylglycerol and phospholipid fractions of the egg total lipids, as well as specific FA ratios. When compared with Pickova (1998), the main difference is found in the n-3/n-6 ratio. No significant differences were found in DHA or AA in between the two species, indicating the general importance of these two FA. EPA was registered in a higher amount in AS, possibly implying a higher presence of dietary EPA and thus reflecting the varying feeding habitats between species. Results indicate that sampled eggs are anadromous and of wild origin. To deepen the understanding of the health condition of the species, future studies should include other molecular- and environmental factors.