Natural fortification of trout with dietary macroalgae and selenised-yeast increases the nutritional contribution in iodine and selenium

•Dietary macroalgae and selenised yeast increased iodine and selenium in trout.•Laminaria digitata is an effective iodine source for trout diets.•Fortified fillets presented a nutritional contribution of 78% DRI for selenium.•Fish nutritional contribution was modulated by diet creating new functional foods.

Fish and seafood consumption are increasing worldwide and the contribution of aquaculture products to consumers' diets is significant. External feeding in aquaculture unlocks the possibility of tailoring fish products with health beneficial compounds. A study was undertaken to evaluate the feed fortification with an iodine-rich macroalgae (Laminaria digitata) and selenised yeast, at its maximum permitted levels, on minerals and vitamins content in rainbow trout edible part. Dietary supplementation resulted in a six-fold increase for iodine and a 2.9-fold increase for selenium contents in trout fillets without altering sensorial traits. The fortified fish presented a nutritional contribution of 12.5% DRI for iodine and 78% DRI for selenium, but all produced fish could supply 80% DRI for vitamin D3. Overall, fish from this trial could be labelled as “high in selenium and high in vitamin D3” under the EFSA definition for a functional food.

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