The researchers studied how different levels of a type of fatty acid called DHA in the diet of Atlantic salmon affected their growth and fatty acid retention. They also looked at how adding other fatty acids like EPA and ARA influenced these outcomes. They found that increasing DHA levels slightly improved growth, with EPA further enhancing growth. DHA retention was highest at very low levels, and adding EPA improved DHA retention efficiency. DPA retention was high at low DHA levels but decreased with more DHA. EPA increased DPA retention efficiency, while ARA had the opposite effect. ARA retention was not affected by DHA but decreased with EPA or ARA additions to the diet.