Bioavailability of selenium from raw or cured selenomethionine-enriched fillets of Atlantic salmon (Salmo salar) assessed in selenium-deficient rats.

The bioavailability of Se from raw and cured selenomethionine-enriched (Se-enriched) salmon fillets was assessed in Se-deficient male albino rats (Mol: Wist). A low-Se Torula yeast feed was supplemented with 0, 50, 100, 150 or 200 microg Se/kg as sodium selenite or as Se from raw or cured Se-enriched salmon. The diets were fed to weanling rats for 10 and 30 d. Bioavailability of Se was assessed by metabolic balance, Se accumulation in femur, muscle, liver and plasma, and induction of Se-dependent glutathione peroxidase (EC 1.11.1.9; GSHpx) in plasma as response parameters. Except for the metabolic balance results, the slope-ratio method was used when calculating Se bioavailability from raw or cured Se-enriched fish fillets (test food) relative to sodium selenite (standard). The data for fractional apparent absorption and fractional retention showed differences (P<0.05) among all three Se sources in the order raw salmon > cured salmon > selenite. At 10 d, Se from raw and cured Se-enriched fish fillets tended to be more bioavailable than selenite. This was supported by the observations for Se accumulation in femur and muscle and induction of GSHpx activity. At 30 d, all response parameters showed a higher bioavailability of Se from raw and cured Se-enriched fish fillets compared with selenite. Differences (P<0.05) in Se accumulation in muscle at 10 and 30d, and differences (P<0.05) in fractional apparent absorption and fractional retention suggested that curing salmon altered the utilisation of Se. The experimental results showed that enrichment of fish fillets with selenomethionine yields fillets with high Se bioavailability.