ABSTRACT
Several studies have indicated the need for selenium (Se) supplementation in plant-based feed to marine carnivorous fish to maintain the natural high levels of Se in marine food products and to cover Se requirements in farmed fish. Se has a narrow range between its toxic and its beneficial effects. Supplementation of aquafeeds with organic Se-methionine (SeMet) forms or inorganic selenite hence requires toxicological assessment to set safe upper limits that protect fish health and consumer safety. This chapter assesses the underlying toxic mechanisms and sensitivity of both dietary selenite and SeMet-yeast in Atlantic salmon by using classic endpoints of Se toxicity, as well as overall metabolomics profiling approaches to assess non-target end-points of toxicity. Based on the established toxic endpoints, safe limits for Se supplementation regarding fish health are assessed using benchmark dose modelling. The chapter also assesses the feed-to-fillet transfer of Se supplementation to Atlantic salmon feeds throughout the seafood production chain.
