High levels of isotope elimination improve precision and allow individual-based measurements of metabolic rates in animals using the doubly labeled water method.
High levels of isotope elimination improve precision and allow individual-based measurements of metabolic rates in animals using the doubly labeled water method.
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DOI：
10.14814/phy2.12552
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发表时间：
2015-11
影响因子：
2.5
通讯作者：
Yoda K
中科院分区：
文献类型：
--
作者：
Shirai M;Niizuma Y;Yamamoto M;Oda E;Ebine N;Oka N;Yoda K
双标记水（DLW）可用于测量自由放养动物的能量消耗，但其在不同物种或环境中的准确性受到质疑。我们研究了同位素消除程度的差异是否会影响DLW方法的精密度和准确度，这可能会根据实验设计或物种的代谢率而有所不同。估计的总能量消耗的DLW方法（TEEdlw）进行了比较，同时通过呼吸测定法（TEEresp）在条纹剪水Calonectris leucomelas，远洋海鸟的实际总能量消耗。受试者被分为3组，分别在地面上休息24 h（A组）、48 h（B组）和水面上休息24 h（C组）。A组的TEEdlw与TEEresp匹配，而与TEEresp相比，B和C组的TEEdlw被高估。然而，与A组相比，B和C组中的TEEdlw降低了同位素分析的变异性，因此具有更高的精度。最佳回归模型（TEEdlw = 1.37 TEEresp-14.12）显示TEEdlw和TEEresp之间具有高度相关性（R2 = 0.82），并允许对条纹剪水的田间代谢率进行校正。我们的研究结果表明，通常假设DLW方法是不适合基于个人的估计可能是不正确的，在某些情况下。尽管使用DLW方法估计代谢率时可能需要校正因子，但更高水平的同位素消除提供了具有高精度的DLW估计值，其可以充分代表相对个体估计值。然而，DLW方法，应谨慎使用时，表征种间差异的能量消耗。
Doubly labeled water (DLW) can be used to measure energy expenditure in free-ranging animals, but questions have been raised about its accuracy in different species or contexts. We investigated whether differences in the extent of isotope elimination affects the precision and accuracy of the DLW method, which can vary according to the experimental design or metabolic rate of the species. Estimated total energy expenditure by the DLW method (TEEdlw) was compared with actual total energy expenditure simultaneously measured via respirometry (TEEresp) in streaked shearwaters Calonectris leucomelas, a pelagic seabird. Subjects were divided into three groups with different experimental conditions: at rest on the ground for 24 h (Group A) or for 48 h (Group B), and at rest on the water for 24 h (Group C). TEEdlw in Group A matched TEEresp, whereas there was an overestimation of TEEdlw in both Groups B and C compared with TEEresp. However, compared with Group A, TEEdlw in Groups B and C had reduced the isotopic analytical variability and thus higher precision. The best regression model (TEEdlw = 1.37 TEEresp − 14.12) showed a high correlation (R2 = 0.82) between TEEdlw and TEEresp and allows a correction factor for field metabolic rates in streaked shearwaters. Our results demonstrate that the commonly made assumption that the DLW method is not appropriate for individual-based estimates may be incorrect in certain circumstances. Although a correction factor may be necessary when using the DLW method to estimate metabolic rate, greater levels of isotope eliminations provides DLW estimates with high precision, which can adequately represent relative individual estimates. Nevertheless, the DLW method, should be used with caution when characterizing interspecies difference of energy expenditures.