TP3 Metals in the Environment: Dietary Concerns in Aquatic Systems
254 Portland Ballroom
1:20 PM - 4:40 PM, Tuesday
() Maternal transport and developmental toxicity of selenium in white sturgeon, Acipenser transmontanus.
Linville, R1, Linares, J1, Kroll, K2, Deng, X1, Van Eenennaam, J1, Hinton, D3, Doroshov, S1, 1 University of California, Davis, CA, USA2 University of Florida, Gainesville, FL, USA3 Duke University, Durham, NC, USA
ABSTRACT- Selenium (Se) is an environmental reproductive toxin that leads to impaired embryonic development, severe malformations, and death in developing birds and fish. The suspected route of Se to the embryo is through maternal vitellogenin during the process of yolk formation. We investigated the maternal transport mechanism and developmental toxicity of Se in the euryhaline fish white sturgeon, Acipenser transmontanus, through two experimental approaches. In the first experiment (October 2001 – June 2002), two groups of eight maturing females were fed diets with normal (1ppm) and elevated (25 – 30 ppm) organic Se for 6 months. Ovulated eggs were removed from females and fertilized, and the resulting embryos were allowed to develop to the point of complete yolk utilization (end of yolk sac larval stage). Se was measured in maternal tissue, plasma vitellogenin (yolk precursor secreted by maternal liver) and ovulated eggs, and correlated with embryo/larval development and survival. In the second experiment (May – July 2004) white sturgeon embryos and yolk sac larvae were microinjected with Se–L–Methionine to mimic maternal transport of Se, and the dose-dependent survival and developmental defects were evaluated. Se was found to disrupt white sturgeon development at environmentally relevant levels. This work is the first to experimentally investigate the mechanism of Se maternal transport in fish and will establish threshold levels of Se in egg yolk that may affect reproduction and stock recruitment of white sturgeon, and possibly other euryhaline fish. White sturgeon were chosen due to their prevalence in an area of selenium enrichment (San Francisco Bay–Delta), their extended period of yolk deposition (two years), and the paucity of Se research on euryhaline fish.
Key words: developmental toxicity, selenium, sturgeon, fish