1. Instability of fecal glucocorticoid metabolites at 4°C: Time to freeze matters
- Author
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Jeffrey Carbillet, Rupert Palme, Marie‐Line Maublanc, Nicolas Cebe, Emmanuelle Gilot‐Fromont, Hélène Verheyden, Benjamin Rey, Unité de recherche Comportement et Ecologie de la Faune Sauvage (CEFS), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS), University of Tartu, University of Veterinary Medicine [Vienna] (Vetmeduni), Laboratoire de Biométrie et Biologie Evolutive - UMR 5558 (LBBE), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS), ECODIV department of the INRAE, and VetAgro Sup
- Subjects
glucocorticoids ,Physiology ,[SDE]Environmental Sciences ,[SDV.BA.ZV]Life Sciences [q-bio]/Animal biology/Vertebrate Zoology ,fecal cortisol metabolites ,Genetics ,mammal ,methodology ,Animal Science and Zoology ,[SDE.BE]Environmental Sciences/Biodiversity and Ecology ,sample preservation ,Molecular Biology ,Ecology, Evolution, Behavior and Systematics - Abstract
International audience; The use of fecal corticosteroid metabolites (FCMs) has proven to be well suited to evaluate adrenocortical activity, a major component of the stress response, particularly in wildlife. As with any tools, confounding factors and drawbacks must be carefully considered. Among them, sample preservation and storage are of particular importance, as they can affect stability of FCMs and lead to biased results and interpretations. Arguably, immediate freezing of fecal samples upon collection is the best practice to preserve FCM integrity, however, for logistical reasons, this condition is rarely feasible in the field. It is generally argued that temporary storage of samples at low above-zero temperature is an acceptable way of preserving samples in the field before freezing them for long-term storage. However, to our knowledge, there is no empirical study that demonstrates the stability of fecal metabolites in samples stored at +4 degrees C. In this study, we collected a fresh fecal sample from 20 captive roe deer, each of which was homogenized and split into three subsamples (60 subsamples in total) to investigate the effects on FCMs levels of temporary storage at +4 degrees C for 24 h and 48 h before freezing versus immediate freezing at -20 degrees C after feces collection. Compared to immediate freezing, mean FCMs levels decreased by 25% every 24 h when feces were stored at +4 degrees C before freezing. The variance of FCMs levels followed the same pattern, leading to a clear reduction in the ability to detect biological effects. Minimizing the storage time at +4 degrees C before freezing should therefore be seriously considered when establishing sampling and storage protocols for feces in the field for adequate hormonal profiling.
- Published
- 2023
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