Fatty Acid Composition of Gilthead Sea Bream (Sparus aurata) Fillets as Affected by Current Changes in Aquafeed Formulation

The aquafeed industry is facing the lack of availability of fish meal and oil. The need of an economic and environmental sustainability has increased the use of plant-derived oils. In order to provide an overview of which ingredients are the most frequently used in GSB diet and as they affect the lipid composition of aquafeeds, we analyzed 26 feed samples collected from farmers. At the same time, 44 farmed GSB were analyzed to compare the fatty acid (FA) composition with 21 wild GSB and 46 GSB farmed in 2005. Twenty-four different ingredients were declared in the analyzed feeds. Fish meal and oil were present in all samples, even if they were not the principal protein and lipid source in the analyzed feeds. If we consider the FA n-3/n-6 ratio, feeds presented a range from the lowest value of 0.35, to the maximum of 2.26. Concerning fish FA, 2014-farmed GSB presented an increased difference with wild GSB, if compared with those reared in 2005, due to the higher presence of oleic and linoleic acid. Our study confirms the increase of use of plant ingredients in aquafeeds and the decrease of the fish meal and oil inclusion in feeds.