In vitro bioaccessibility of macro and trace elements in biofortified and conventional farmed gilthead seabream (Sparus aurata) and common carp (Cyprinus carpio)

Biofortification is a promising strategy to improve the nutrient profile of farmed fish but requires consideration of the nutrient bioaccessible fraction. In this study, the in vitro bioaccessibility of macro and trace elements was investigated in biofortified and conventional farmed gilthead seabream and common carp, also taking into account the effect of cooking (by steaming). Biofortification enhanced iodine and selenium levels in seabream and carp fillets. Steaming increased iodine and selenium contents in biofortified seabream, and increased selenium and decreased copper levels in biofortified carp. Higher iodine bioaccessibilty (> 80%) was observed in biofortified seabream compared to biofortified carp (45%). In both species, selenium, iron, and zinc bioaccessibility was ≥ 70%. Upon steaming iodine and iron bioaccessibility decreased in seabream, while selenium bioaccessibility decreased in carp. The consumption of steamed biofortified seabream and carp contributes to significantly higher daily intakes of iodine (up to 12% and 10%, respectively) and selenium (up to 54% and above 100%, respectively) compared to conventional counterparts. The present study demonstrates the potential of developing innovative biofortified farmed fish using natural sustainable feed ingredients to improve the intake of important nutrients for human health.

Highlights: - Iodine bioaccessibility is 80% in seabream and lower than 50% in carp. - Selenium, iron and zinc bioaccessibility were always above 70%. - Overall, bioaccessibility decreased after steaming (e.g., K: lower than 50%). - The availability of I and Se for absorption following the digestive process was higher in biofortified fillets.