Effects of crude rapeseed oil on lipid composition in Arctic charr Salvelinus alpinus

This study investigated the effects of crude rapeseed oil (RO) on lipid content and composition in muscle and liver of Arctic charr Salvelinus alpinus. Triplicate groups were fed diets containing fish oil (FO):RO ratio of 100:0, 75:25, 50:50 and 25:75 until two‐fold mass increase. Total lipid content increased significantly in the liver with higher proportion of RO in the diet. Profound effects were seen in the fatty acid composition in the analysed tissues with a reduction in 20:5n‐3 and 22:6n‐3 and an increase in 18:2n‐6 with higher RO content in the diets. A drop in cholesterol content was seen at 25% inclusion of RO in both tissues. Wild‐caught fish contained a considerably higher amount of 20:4n‐6 in both storage and membrane lipids of white muscle compared with the experimental fish.