Alterations in the sterol signature of detritivorous fish along pollution gradients in the Rio de la Plata basin (Argentina): From plant to sewage-based diet
Alterations in the sterol signature of detritivorous fish along pollution gradients in the Rio de la Plata basin (Argentina): From plant to sewage-based diet
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DOI：
10.1016/j.envres.2020.109351
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发表时间：
2020-05-01
影响因子：
8.3
通讯作者：
Carlos Colombo, Juan
中科院分区：
文献类型：
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作者：
Demian Speranza, Eric;Colombo, Manuel;Carlos Colombo, Juan
为了评价污水污染对南美鱼类摄食的影响，用气相色谱-质谱法分析了沿拉普拉塔盆地1200公里处采集的鱼类肌肉(n：144)中的16种甾醇生物标志物。甾醇浓度相当均匀(2.4+/-1.3 mg g(-1)干重)，但它们在脂肪中的比例变化很大，与体重和脂肪含量呈负相关，反映出与鱼类生长过程中脂肪的快速积累相比，甾醇的保守特征。正如预期的那样，肌肉中的甾醇特征主要是胆固醇(占总甾醇的92+/-4.5%)，但它表现出显著的多样性，粪便中含有不同比例的辅前列醇(4.0+/-4.4%)和植物甾醇(3.1+/-1.9%，如谷甾醇和菜籽甾醇)。肌肉甾醇表现出鲜明的地理差异，从盆地北部地区(N：巴拉那和乌拉圭河)的植物来源碎屑到布宜诺斯艾利斯(BA)以污水为主的输入。来自BA的鱼类脂肪较多(脂肪：35+/-18vs.15+/-9.0%)，总甾醇含量较高(2.6+/-1.3vs.1.9+/-1.0 mg g(-1))，丰富的辅前列醇(5.3+/-4.4vs.0.46+/-1.1%)和较低的植物甾醇(2.6+/-1.6vs.4.6+/-2.0%)，反映出北方的食物转向人为有机物质，而不是植物碎屑。因此，BA鱼表现出较低的植物/粪便甾醇比率(0.37+/-0.21vs.0.91+/-0.12)和较高的Copro/epicoprostanol比率(0.95+/-0.082 vs.0.51+/-0.25)，这表明新鲜的粪便输入为该地点提供了宝贵的易吸收有机物质供应。此外，允许区分迁徙鱼类和BA的类固醇特征在北部900公里处采集(以前通过它们的污染物指纹和生化成分来识别)。事实上，副前列腺素浓度与盆地沿线的人类种群有直接关系，突显了粪便中的甾醇生物标记物作为受污染鱼类种群示踪剂的用处。
In order to assess the impact of sewage pollution on the diet of the strict detritivorous and migratory South American fish, Prochilodus lineams, 16 sterol biomarkers were analyzed by gas chromatography-mass spectrometry from fish muscle (n: 144) collected along 1200 km in the Rio de la Plata basin. Sterol concentrations were fairly homogeneous (2.4 +/- 1.3 mg g(-1) dry weight), but their proportion in lipids was highly variable and inversely related to both body mass and lipid contents, reflecting the more conservative character of sterols compared to the rapid accumulation of fat as fish grows. As expected, the muscle sterol signature was widely dominated by cholesterol (92 +/- 4.5% of total sterols), but it exhibited a remarkable diversity with variable proportions of fecal coprostanol (4.0 +/- 4.4%) and plant sterols (3.1 +/- 1.9%, e.g. sitosterol and campesterol). Muscle sterols exhibited contrasting geographical differences associated with dietary shifts from plant-derived detritus in the northern reaches of the basin (N: Parana and Uruguay Rivers), to sewage dominated inputs at Buenos Aires (BA). Fish from BA are fattier (lipids: 35 +/- 18 vs. 15 +/- 9.0% at N), with higher total sterol contents (2.6 +/- 1.3 vs. 1.9 +/- 1.0 mg g(-1)), abundant coprostanol (5.3 +/- 4.4 vs. 0.46 +/- 1.1%) and lower plant sterols (2.6 +/- 1.6 vs 4.6 +/- 2.0%), reflecting a diet shifted to anthropogenic organic matter as opposed to vegetal detritus in the north. Accordingly, BA fish presented lower phyto/fecal sterol ratios (0.37 +/- 0.21 vs. 0.91 +/- 0.12 at N) and higher copro/epicoprostanol ratios (0.95 +/- 0.082 vs 0.51 +/- 0.25 at N), indicating fresh fecal inputs which provide a valuable supply of easily absorbed organic matter at this site. In addition, the sterol signature allowed to distinguish migratory fish from BA collected 900 km north (previously identified by their pollutant fingerprint and biochemical composition). In fact, coprostanol concentrations show a direct relationship with human populations along the basin, highlighting the usefulness of fecal sterol biomarkers as tracers of polluted fish stocks.