Lee Seunghyung, Fadel James G, Haller Liran Y, Verhille Christine E, Fangue Nann A, Hung Silas S O
Department of Animal Science, University of California, Davis, CA 95616, USA.
Department of Wildlife, Fish and Conservation Biology, University of California, Davis, CA 95616, USA.
Comp Biochem Physiol A Mol Integr Physiol. 2015 Oct;188:156-67. doi: 10.1016/j.cbpa.2015.06.027. Epub 2015 Jun 27.
A multistressor study was conducted to investigate interactive effects of nutritional status and salinity on osmoregulation of juvenile white sturgeon. Our hypothesis was that lower nutritional status would decrease the salinity tolerance of juvenile white sturgeon. A four-week feed restriction (12.5%, 25%, 50%, 100% of optimum feeding rate: OFR defined as the rate (% body weight per day) at which growth is maximal) trial was performed, and relevant indices of nutritional status were measured. Following the trial, sturgeon were acutely exposed to various salinities (0, 8, 16, 24 ppt) for 120 h, and relevant osmoregulatory measurements were made at 12, 72, and 120 h post-salinity exposures. The feed-restriction trial resulted in a graded nutritional response with the most feed-restricted group (12.5% OFR) showing the lowest nutritional status. The salinity exposure trial showed clear evidence that lower nutritional status decreased the salinity tolerance of juvenile white sturgeon. Increasing salinities resulted in significant alterations in osmoregulatory indices of all feeding groups; however, a significantly slower acclimatory response to 24 ppt was detected in the most feed-restricted group compared to the non-feed-restricted group (100% OFR). Furthermore, evaluation of the effect of nutritional status on the relationship between osmoregulatory measurements and body size showed that there was a significant negative relationship between osmoregulatory performance and body size within the most feed-restricted group. This suggests that there is a certain body size range (200-300 g based on our finding) where juvenile white sturgeon can maximize osmoregulatory capacity at a salinity of 24 ppt.
进行了一项多应激因素研究，以调查营养状况和盐度对幼年白鲟渗透调节的交互作用。我们的假设是，较低的营养状况会降低幼年白鲟的盐度耐受性。进行了为期四周的限食试验（最佳投喂率的12.5%、25%、50%、100%：最佳投喂率定义为生长最大化时的投喂率（每天体重的百分比）），并测量了营养状况的相关指标。试验结束后，将鲟鱼急性暴露于不同盐度（0、8、16、24ppt）下120小时，并在盐度暴露后12、72和120小时进行相关的渗透调节测量。限食试验导致了分级的营养反应，限食程度最高的组（12.5%最佳投喂率）营养状况最低。盐度暴露试验清楚地表明，较低的营养状况会降低幼年白鲟的盐度耐受性。盐度增加导致所有投喂组的渗透调节指标发生显著变化；然而，与非限食组（100%最佳投喂率）相比，限食程度最高的组对24ppt的适应性反应明显较慢。此外，评估营养状况对渗透调节测量与体型之间关系的影响表明，在限食程度最高的组中，渗透调节性能与体型之间存在显著的负相关关系。这表明存在一定的体型范围（根据我们的研究结果为200-300克），在此范围内幼年白鲟在24ppt盐度下可使渗透调节能力最大化。
