Irstea, Hydrosystems and Bioprocesses Research Unit, Antony, France.
Rapid Commun Mass Spectrom. 2012 Jul 30;26(14):1603-8. doi: 10.1002/rcm.6265.
Dorsal white muscle is the standard tissue analysed in fish trophic studies using stable isotope analyses. However, sampling white muscle often implies the sacrifice of fish. Thus, we examined whether the non-lethal sampling of fin tissue can substitute muscle sampling in food web studies.
Analysing muscle and fin δ(15)N and δ(13)C values of 466 European freshwater fish (14 species) with an elemental analyser coupled with an isotope ratio mass spectrometer, we compared the isotope values of the two tissues. Correlations between fin and muscle isotope ratios were examined for all fish together and specifically for 12 species. We further proposed four methods of assessing muscle from fin isotope ratios and estimated the errors made using these muscle surrogates.
Despite significant differences between isotope values of the two tissues, fin and muscle isotopic signals are strongly correlated. Muscle values, estimated with raw fin isotope ratios (1st method), induce an error of ca. 1‰ for both isotopes. In comparison, specific (2nd method) or general (3rd method) correlations provide meaningful corrections of fin isotope ratios (errors <0.6‰). On the other hand, relationships, established for Australian tropical fish, only give poor muscle estimates (errors >0.8‰).
There is little chance that a global model can be created. However, the 2nd and 3rd methods of estimating muscle values from fin isotope ratios should provide an acceptable level of error for the studies of European freshwater food web. We thus recommend that future studies use fin tissue as a non-lethal surrogate for muscle.
在使用稳定同位素分析进行鱼类营养研究时，通常会分析背侧白色肌肉组织。然而，采集白色肌肉组织通常意味着鱼类会被牺牲。因此，我们研究了是否可以通过采集鳍组织来替代肌肉组织进行食物网研究。
我们使用元素分析仪与同位素质谱仪相结合，分析了 466 种欧洲淡水鱼（14 个物种）的肌肉和鳍δ(15)N 和 δ(13)C 值，比较了这两种组织的同位素值。我们还综合所有鱼类以及 12 个特定物种，研究了鳍和肌肉同位素比值之间的相关性。我们进一步提出了四种从鳍同位素比值评估肌肉的方法，并估计了使用这些肌肉替代物所产生的误差。
尽管两种组织的同位素值存在显著差异，但鳍和肌肉的同位素信号具有很强的相关性。使用原始鳍同位素比值（第一种方法）估计肌肉值，两种同位素的误差约为 1‰。相比之下，特定（第二种方法）或一般（第三种方法）相关性可提供对鳍同位素比值的有意义的校正（误差 <0.6‰）。另一方面，为澳大利亚热带鱼类建立的关系仅能提供较差的肌肉估计值（误差 >0.8‰）。
不太可能创建一个全球模型。但是，从鳍同位素比值估算肌肉值的第二种和第三种方法，应该可以为欧洲淡水食物网的研究提供可接受的误差水平。因此，我们建议未来的研究使用鳍组织作为非致死性的肌肉替代物。
