Influence of handling stress and fasting on estimates of ammonium excretion by tadpoles and fish: recommendations for designing excretion experiments
Influence of handling stress and fasting on estimates of ammonium excretion by tadpoles and fish: recommendations for designing excretion experiments
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处理压力和禁食对蝌蚪和鱼铵排泄估计的影响：设计排泄实验的建议
DOI：
10.4319/lom.2009.7.1
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
J. D. Reeve
中科院分区：
文献类型：
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作者：
M. Whiles;A. Huryn;B. W. Taylor;J. D. Reeve
排泄率估计对于将消费者与生物地球化学过程联系起来很重要。在室内短期孵育是研究的常用方法。然而，这可能会导致不准确，因为有充分证据表明排泄量随时间下降，这通常归因于禁食。然而，另一种解释是，在从处理压力中恢复期间，排泄减慢。虽然较短的孵育时间可能会减少禁食效应，但较长的孵育时间可以从处理中恢复。尽管这两种观点都有优点并且并不相互排斥，但缺乏确定最佳孵育时间的尝试。我们研究了处理压力和禁食对杂食性蝌蚪和捕食性鱼类NH4+排泄的影响。禁食不影响蝌蚪排泄至少6小时。相反，处理应激似乎会导致最初的排泄升高，因此更长的孵育时间是合适的。禁食和处理应激影响鱼类排泄，中间孵育（约30分钟）似乎是最合适的。我们还发现，铵的测量混淆了排泄产物的浓度增加，在较长的孵育。我们建议研究包括孵育时间试验并校正潜在的基质效应。处理和禁食的影响可能因生物体和实验程序而异，两者都可以使用我们描述的程序来解释。
Excretion rate estimates are important for linking consumers to biogeochemical processes. Short‐term incubations in chambers are a common approach for studies. This, however, may result in inaccuracies due to a welldocumented decline in excretion with time, which is often attributed to fasting. An alternative explanation, however, is that excretion slows during recovery from handling stress. Whereas shorter incubations may reduce fasting effects, longer incubations can allow for recovery from handling. Although both views have merit and are not mutually exclusive, attempts to identify optimal incubation times are lacking. We examined effects of handling stress and fasting on NH4+ excretion by omnivorous tadpoles and predatory fish. Fasting did not influence tadpole excretion for at least 6 h. Rather, handling stress appeared to cause initially elevated excretion, and thus longer incubations were appropriate. Fasting and handling stress influenced fish excretion, and intermediate incubations (~30 min) appeared most appropriate. We also found that ammonium measurements were confounded by increasing concentrations of excretory products in longer incubations. We recommend that studies include incubation time trials and correct for potential matrix effects. Effects of handling and fasting likely vary with organism and experimental procedures, and both can be accounted for using the procedures we describe.