PARENT SESSION
PM13 - Selenium: Sources, Pathways, Receptors
Monday, 18 November 2002
8:00 AM to 6:30 PM
Exhibit Hall
(P334) The effects of selenium bioaccumulation on larval rainbow trout (Oncorhynchus mykiss) after 90-days of dietary selenomethionine exposure.
Kim, Rickey1, Schlenk, Daniel*,1, Bay, Steve3, 1 Department of Environmental Sciences, University of California, Riverside, Riverside, CA, USA3
ABSTRACT- The goal of this study was to determine whether tissue accumulation of selenium can cause a significant impairment of fish populations of San Diego Creek, in Orange County, CA. Selenium is found in elevated levels in the creek (>5mg/L). A 90-day selenomethionine (SeMe) exposure was conducted to determine the effects of selenomethionine on the growth, survival and whole body Se concentration in larval rainbow trout. The reduced and oxidized glutathione and thiobarbituric acid reactive substance (TBARS) levels were also measured in the livers of the trout to assess oxidative damage. Larval rainbow trout that were exposed to dietary SeMe demonstrated a significant reduction in growth condition index at 30- and 90-days for all exposures (P<0.05). All samples exhibited significant weight gain from each previous sampling period. Wholebody selenium concentration was highest at 60-days of exposure in those animals that were fed 18 ppm SeMe. There was a significant increase in the wholebody selenium concentration from 30 to 60 days of exposure at the highest dose. Exposure to 4.6, 12 and 18 mg SeMe/g diet for 90-days resulted in reduced body weight as compared to the controls and the fork length was also significantly reduced in fish that were fed 18 mg SeMe/g dry diet for 90-days (p<0.05). The NOEC was <4.6mg/g (P<0.001). These results also indicate a threshold of 2.5 mg/g as a body burden criterion for reduced condition indices, percent growth and weight.
Key words: Selenomethionine