Vitamin D in Wild and Farmed Atlantic Salmon (Salmo Salar)—What Do We Know?

Salmon have been widely publicized as a good dietary source of vitamin D, but recent data points to large variation in vitamin D content and differences between wild and farmed salmon. We aimed to: (1) investigate the content of vitamin D in Atlantic salmon (Salmo salar) in wild species caught in two different waters, (2) perform a 12-week feeding trial in farmed Salmo salar with 270–1440 µg vitamin D(3)/kg feed (4–20 times maximum level in the EU) and (3) conduct a review for the published data on the content of vitamin D in salmonids. Content of vitamin D(3) in the fillet from wild salmon caught in the Baltic Sea and the North Sea was significantly different (p < 0.05), being 18.5 ± 4.6 µg/100 g and 9.4 ± 1.9 µg/100 g, respectively. In the farmed salmon the content ranged from 2.9 ± 0.7 µg vitamin D(3)/100 g to 9.5 ± 0.7 µg vitamin D(3)/100 g. Data from 2018 shows that farmed salmon contained 2.3–7.3 µg vitamin D(3)/100 g. Information on the content of vitamin D in wild and farmed salmonids is very limited, which calls for further research to ensure a sustainable production of salmon with adequate vitamin D.