Effects of dietary methylmercury on growth performance and tissue burden in juvenile green (Acipenser medirostris) and white sturgeon (A. transmontanus)

Effects of feed restriction on the upper temperature tolerance and heat shock response in juvenile green and white sturgeon

“…Due to current and projected food web alterations and temperature increase in the SFBD, investigating the effects of feed restriction on whole-organism upper thermal tolerance (measured as CTMax) and the temperature sensitivity of the heat shock response (measured as Hsc/Hsp70 protein levels) of green and white sturgeon is necessary to determine how changes in food availability might influence physiological performance of each sturgeon species when faced with increased temperature. Similar to previous studies reporting species-specific differences in sensitivity to chemical contaminants (Lee et al, 2011(Lee et al, , 2012De Riu et al, 2014) and changes in water velocities near water-diversion fish screens (Poletto et al, 2014), green sturgeon may also be less tolerant than white sturgeon to temperature stress when food is limited. As a result, concurrent environmental alterations including increasing temperature and reduced food availability driven by anthropogenic activities may have a relatively larger impact on resilience of the threatened green sturgeon.…”

“…Comparative studies of white and green sturgeon from our group have shown that these species differ significantly in their sensitivity to chemical contaminants such as mercury and selenium (Lee et al, 2011(Lee et al, , 2012De Riu et al, 2014), to salinity challenges Lee et al, 2015) and show behavioral differences to variable water velocities around waterdiversions (e.g., Poletto et al, 2014). Taken together, results from these studies demonstrate that green sturgeon in general are more sensitive to environmental change than white sturgeon and therefore white sturgeon serve as a poor surrogate species for green sturgeon when it comes to understanding stress tolerance, effects of food limitation, and overall vulnerability to GCC.…”

Deficient and excess dietary selenium levels affect growth performance, blood cells apoptosis and liver HSP70 expression in juvenile yellow catfish Pelteobagrus fulvidraco

“…In our study, a dose-response relationship of dietary Se and the liver's Se concentration, its HSI, GPx activity was observed up to 6.5 mg Se/kg diet, liver's Se concentration, its HSI, GPx activity as bio-indicators of dietary Se exposure. In contrast, a decrease in the HSI was observed in the green sturgeon (Acipenser medirostris) (Lee et al 2011;Riu et al 2014) and juvenile red swamp crayfish (Procambarus clarkia) (DÖ rr et al 2013) as dietary Se increased. The authors proposed that a decreased HSI might reflect the depletion in energy reserves under Se-induced stress conditions Riu et al 2014).…”

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“…Fo r this reason, direct total concentration of Hg was measured instead of MeHg (Bloom, 1992;A mlund, Lundebye, & Berntssen, 2007). Hg analyzer (DMA-80, M ilestone, Inc., Shelton, CT) was used to determine tissue Hg concentration following the method similar to the one used in Lee et al (2011). A certified reference material (DORM -2 dogfish liver, National Research Council, Canada) was used simultaneously during the analyses.…”