Therefore, the particular aims of the present study were to confirm the requirement for dietary phospholipid in Atlantic salmon, better define the level of requirement, and further establish the period of require-ment. To this end, Atlantic salmon fry were fed diets containing either krill oil or soybean lecithin in a regression design at five levels from first feeding through to parr–smolt transformation. Analyses focused on growth, mortality, vertebral malformation and intestinal histology (steatosis).