A comparison of carbon and nitrogen stable isotope ratios of fish tissues following lipid extractions with non-polar and traditional chloroform/methanol solvent systems
A comparison of carbon and nitrogen stable isotope ratios of fish tissues following lipid extractions with non-polar and traditional chloroform/methanol solvent systems
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DOI：
10.1002/rcm.3471
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发表时间：
2008-04-01
影响因子：
2
通讯作者：
Lutcavage, Molly E.
中科院分区：
文献类型：
--
作者：
Logan, John M.;Lutcavage, Molly E.
稳定同位素比值作为动物饮食的化学示踪剂，并用于研究食物网动态。由于碳稳定同位素值受组织脂质含量的影响，许多提取方法已被用来消除脂质偏差，但在某些物种和组织中，提取也改变氮同位素值。我们分析了大西洋蓝鳍金枪鱼肝脏和白色肌肉，以及整个大西洋鲱鱼，鱼组织中的δ C-13和δ N-15，这些鱼组织涵盖了广泛的脂质含量（散装C：N 3.1-12.5）。为了比较来自传统氯仿/甲醇提取与非极性溶剂替代物的Δ C-13和Δ N-15值，我们分析了以下样品：（1）不处理，（2）使用氯仿/甲醇（2：1）去除脂质，和（3）使用氯仿、乙醚或己烷的索氏提取。氯仿/甲醇和氯仿提取产生最低的C：N值和最高的Δ C-13值。在蓝鳍金枪鱼，氯仿和己烷提取显着改变肝脏δ N-15。并且所有方法都显著改变了白色肌肉中的Δ N-15值。整个大西洋鲱鱼三角洲N-15没有改变任何提取方法，而2：1氯仿/甲醇提取最完全去除鱼组织脂质成分。我们的研究结果表明，Δ N-15的影响并不限于常见的氯仿/甲醇提取，并建议氯仿/甲醇是最有效的提取Δ C-13校正。鉴于所有测试方法中Δ N-15改变的证据，应进一步探索数学校正方法作为脂质校正的替代方法。版权所有（C）2008约翰威利父子有限公司
Stable isotope ratios act as chemical tracers of animal diet, and are used to study food web dynamics. Because carbon stable isotope values are influenced by tissue lipid content, a number of extraction methods have been used to remove lipid bias, but, in some species and tissues, extractions also alter nitrogen isotope values. We have analyzed delta C-13 and delta N-15 in Atlantic bluefin tuna liver and white muscle, and whole Atlantic herring, fish tissues covering a wide range of lipid content (bulk C:N 3.1-12.5). In order to compare delta C-13 and delta N-15 values from traditional chloroform/methanol extractions with non-polar solvent alternatives, we analyzed samples following (1) no treatment, (2) lipid removal using chloroform/methanol (2:1), and (3) Soxhlet extractions using chloroform, diethyl ether or hexane. Chloroform/methanol and chloroform extractions produced the lowest C:N values and highest delta C-13 values. In bluefin tuna, chloroform and hexane extractions significantly altered liver delta N-15. and all methods significantly altered delta N-15 values in white muscle. Whole Atlantic herring delta N-15 was not altered by any extraction method, while the 2:1 chloroform/methanol extraction most completely removed fish tissue lipid components. Our results indicate that delta N-15 effects are not limited to common chloroform/methanol extractions and suggest that chloroform/methanol is the most effective extraction for delta C-13 correction. Given evidence for delta N-15 alteration among all tested methods, mathematical correction approaches should be further explored as an alternative to lipid correction. Copyright (C) 2008 John Wiley & Sons, Ltd.