Effect of selenium deficiency on cuticle integrity in the Cladocera (Crustacea).

Abstract

Daphnia pulex de Geer and D. magna Straus populations cannot be maintained in defined (sensu stricto) media containing less than 0.1 ppb S. A concentration of 1 ppb is sufficient to satisfy minimal needs in otherwise sufficient media. In the 1st generation with no Se added to the medium or detected in it, media deficiency is shown by a premature cuticle deterioration visually similar to senescence, by progressive loss of distal segments of 2nd antennae (primary swimming appendages) and by a shortened lifespan. No progeny attain reproductive maturity in the 2nd generation. Although experimental animals in prime condition exhibit a shortened lifespan in the 1st generation maintained at 0.5 ppb Se, culture lines can be maintained at 0.5 ppb for indefinite numbers of generations if established as young orthoclones. Tests in organic-rich media indicate a significant sparing effect of organic additions. This Se requirement is reminiscent of that for the stability of feathers in domestic fowl.