SELENIUM STATUS IN CHARADRIIFORMES - TISSUE DISTRIBUTION AND SEASONAL, GEOGRAPHICAL, AND SPECIES VARIATION

The distribution of selenium in a marine wader, the Oystercatcher (Hae matopus ostralegus) is given by the levels in 15 tissues and plasma. R ed blood cells (RBC) contain the highest level (23 mg/kg dry wt) follo wed by liver, lung, and kidney (17-19 mg/kg). Most other tissues range from 3-10 mg/kg. The average kidney and liver concentrations of the O ystercatcher belong to the concentrations characteristic in birds. How ever, the Oystercatcher's tissue selenium concentrations are in genera l four- to fivefold mammalian levels, but in liver and lung, 11- to 13 -fold and in the RBC, 12- to 33-fold. The selenium plasma and RBC leve ls of the Oystercatcher vary during the year from 280 to 410 mu g/L an d 13 to 30 mg/kg dry wt, respectively; the plasma concentrations are p ositively correlated with the RBC selenium concentrations. An overview of literature data shows that the selenium kidney and liver concentra tions of birds do not vary with geographical latitude and size (length ) of the birds. In species of the orders Charadriiformes and Procellar iiformes, high selenium kidney, and to a lesser extent liver, concentr ations may occur. A function of selenium in antioxidation is suggested .