Influence of dietary menadione nicotinamide bisulphite (vitamin K3) and phylloquinone (vitamin K1) on Atlantic salmon (Salmo salar L.) tissue levels,determined by high‐performance liquid chromatography with fluorescence detection

The aim of the present study was to investigate the retention of menadione nicotinamide bisulphite (MNB; vitamin K₃) and phylloquinone (vitamin K₁) in Atlantic salmon (Salmo salar L.). Another objective was to find a reliable method for determination of menadione in fish feed, and to include and validate more matrices in the methods for phylloquinone and menaquinones (vitamin K₂). Duplicate tanks of Atlantic salmon (～93 g) were fed four levels (0–1000 mg menadione kg^?1 feed) of MNB for 9 weeks. The concentration of menadione and phylloquinone in the feed and the concentration of phylloquinone and menaquinone‐4 (MK‐4) in the tissues were determined. The analysed concentration of dietary menadione found in feed indicated a substantial loss of MNB during feed production. This assumption was supported by screening 15 commercial fish feed samples which also revealed menadione concentrations far below the recommended level. MNB fed salmon showed only a minor increase in liver MK‐4 concentration, compared to salmon fed phylloquinone which had a considerably higher level of liver phylloquinone, indicating a higher retention of phylloquinone compared to menadione in Atlantic salmon. Due to highly varying stability and bioavailability of the different vitamin K derivatives, vitamin K supplementation in fish feed needs a revision.