1. The present study was conducted to determine the biological availability to rats of the selenium in four high-Se seafoods: crab (CuZlinectes supidus), oyster (Crassostrea virginica), shrimp (Penueus duorarum) and Baltic herring (Clupea harengus).
2. Weanling male rats were fed on a Se-deficient Torula yeast diet for 4 weeks followed by either continued depletion or repletion for 4 weeks with 0.05, 0.1 or 0.2 μg Se as selenite/g, or 0.1 or 0.2 μg Se as freeze-dried cooked test food/g. Plasma and liver Se levels or glutathione peroxidase (EC 184.108.40.206; GSH-Px) activities were used as indicators of body Se status.
3. Except for oysters, the biological availability of Se in all these seafoods was close to that of selenite (selenite 100%) when the criterion used was either plasma Se level or plasma GSH-Px activity.
4. By the criterion of increased liver Se level of restored hepatic GSH-Px activity, only herringSe had a biological availability comparable to that of selenite-Se under all conditions tested, whereas crab-Se and oyster-Se were distinctly inferior in this regard.
5. Increasing the amount of crab-Se, oyster-Se or shrimp-Se supplied in the diet from 0.1 to 0.2 μg/g changed the apparent availability (%) of Se for hepatic GSH-Px restoration from 38 to 78, 22 to 53 and 57 to 90 respectively.
6. The present study demonstrates that the availability of Se in certain foods is a function of the criterion chosen, the level of Se supplied in the diet, and possibly other unknown interacting dietary factors.