Can increasing vitamin D in the feed make salmon just as vitamin D-rich in winter as in summer?
How does feed affect vitamin D levels in farmed salmon?
In a new study published in Aquaculture Nutrition, FishLab AS has contributed analyses of vitamin D₃ and associated metabolites in blood plasma, liver and muscle tissue from Atlantic salmon. The analyses were central to investigating how increased dietary vitamin D₃ supplementation affects the fish's vitamin D status across different seasons.
The study was conducted under commercial farming conditions in Rogaland, where the salmon were fed either standard feed or feed with approximately ten times higher vitamin D₃ content over 32 weeks.
The results showed that the increased vitamin content in the feed resulted in significantly higher vitamin D₃ concentrations in all tissues examined. In blood plasma, levels were up to six times higher in the group that received extra vitamin D₃. The supplement thus helped to compensate for the lower vitamin D levels naturally observed during the winter months.
What does this mean for fish health and the nutritional value of salmon?
Vitamin D is important for the physiological functions of fish, while salmon is a valuable source of vitamin D in the human diet. The study showed that increased supply of vitamin D₃ through the feed resulted in higher concentrations in the fish's tissues, with no observed negative effects on growth or mortality during the experimental period. The findings thus suggest that targeted supply of vitamin D₃ can help maintain vitamin D content in farmed salmon throughout the year.
FishLab is proud to contribute analytical expertise that strengthens the knowledge base for research on fish health and nutrition.
The study is published in Aquaculture Nutrition (2026): "Elevated Dietary Vitamin D Supplementation During Winter can Mimic Vitamin D Levels Induced by Summer Daylight Exposure in Atlantic Salmon".
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