Department of Environmental Science, Ecology Building, Lund University, SE-223 62 Lund, Sweden.
Environ Pollut. 2009 Dec;157(12):3396-403. doi: 10.1016/j.envpol.2009.06.026. Epub 2009 Jul 18.
Atlantic salmon accumulate high levels of contaminants such as polychlorinated biphenyls (PCBs) in their lipids during the adult growth phase spent at sea. The lipids are later utilized during migration for swimming and biological adaptations. We hypothesize that migrating salmons' biotransformation processes are affected by the high levels of built-up PCBs compared to salmon that in a pre-migrational stage. For these analyses we sampled adult Atlantic salmon during migration in the Swedish River Mörrum and measured the 21 most common PCB congeners ( summation operatorPCB) and lipid levels in muscle tissue, aryl hydrocarbon receptor (AHR2) and cytochrome P4501A1 (CYP1A1) transcript levels as well as ethoxyresorufin-O-deethylase activity (EROD) in liver. We also determined which AHR2 genotypes the salmon carried. We show that EROD activity is correlated to CYP1A1 level but not to summation operatorPCB concentration. summation operatorPCB concentration does not predict levels of neither the AHR2 nor CYP1A1 genes. We find no associations between specific AHR2 transcription levels and AHR2 genotypes or a correlation between AHR2 and CYP1A1 transcription levels, which is in direct contrast to pre-migrational adult salmon from the Baltic Sea. When we compare River Mörrum to salmon we have previously sampled in the Baltic Sea we show that migrating salmon have significantly lower lipid levels in their muscles; higher muscle concentrations of summation operatorPCB on a lipid basis; and significantly lower CYP1A1 and EROD levels compared to salmon from the Baltic Sea. Also, transcript levels of three out of four AHR2 genes are significantly different. In conclusion, migrating Swedish Atlantic salmon carry higher concentrations of PCBs in their lipids compared to salmon in the Baltic Sea, but have lower activation of biotransformation genes and enzymes. Our results indicate that accumulated pollutants from the Baltic Sea are deactivated inside the migrating salmon's lipid tissues and increase in concentration when migration is initiated thereby limiting their impact on biotransformation processes.
在成年生长阶段，大西洋鲑鱼在海水中会在其脂肪中积累高水平的污染物，如多氯联苯（PCBs）。这些脂肪在洄游过程中用于游泳和生物适应。我们假设与处于预洄游阶段的鲑鱼相比，洄游鲑鱼的生物转化过程受到积累的高水平 PCBs 的影响。为此，我们在瑞典 Mörrum 河的鲑鱼洄游期间采样了成年大西洋鲑鱼，并测量了肌肉组织中的 21 种最常见的 PCB 同系物（∑PCB）和脂质水平、芳烃受体（AHR2）和细胞色素 P4501A1（CYP1A1）转录水平以及肝脏中的乙氧基 RESO 荧光素-O-脱乙基酶活性（EROD）。我们还确定了鲑鱼携带的 AHR2 基因型。我们表明，EROD 活性与 CYP1A1 水平相关，但与∑PCB 浓度无关。∑PCB 浓度既不能预测 AHR2 基因也不能预测 CYP1A1 基因的水平。我们没有发现特定 AHR2 转录水平与 AHR2 基因型之间的相关性，也没有发现 AHR2 和 CYP1A1 转录水平之间的相关性，这与波罗的海的预洄游成年鲑鱼直接相反。当我们将 Mörrum 河与我们之前在波罗的海采样的鲑鱼进行比较时，我们发现洄游鲑鱼肌肉中的脂肪含量明显较低；以脂肪为基础，肌肉中∑PCB 的浓度更高；与波罗的海的鲑鱼相比，CYP1A1 和 EROD 的水平明显较低。此外，四个 AHR2 基因中的三个的转录水平有显著差异。总之，与波罗的海的鲑鱼相比，迁移到瑞典的大西洋鲑鱼在其脂肪中积累了更高浓度的 PCBs，但生物转化基因和酶的激活水平较低。我们的结果表明，来自波罗的海的积累污染物在迁移鲑鱼的脂肪组织内失活，并在开始迁移时增加浓度，从而限制了它们对生物转化过程的影响。
