title: Validation of a field-friendly extraction and storage method to monitor fecal steroid metabolites in wild orangutans.
abstract: Measuring hormone metabolites from feces is the most often used method to assess hormonal status in wildlife. Although immediate freezing of fecal samples collected in the field is the best method to minimize the risk of degradation of hormones over time, this is often not possible in remote field sites. Therefore, alternative storage and preservation methods for fecal samples are required in these conditions. We conducted an experiment to investigate if fecal glucocorticoid (FGCM) and progesterone metabolite (pregnanediol-3-glucuronide; PdG) levels measured from samples that were extracted with a simple, field-friendly methodology correlate with those generated from frozen samples. We also evaluated whether storing fecal samples in alcohol is a suitable alternative to preserve FGCM and PdG concentrations long-term (i.e. over a 9-month period) at locations where fecal extraction is not feasible. Finally, we tested if the hormone concentrations in unpreserved fecal samples of orangutans change over 14 h when stored at ambient conditions, representing the maximum duration between sample collection and return to the camp. FGCM and PdG levels measured from samples that were extracted with the field-friendly method showed strong correlations with those generated from frozen samples, and mean levels did not differ significantly between these methods. FGCM concentrations showed no significant change compared to control samples when fecal samples were stored for up to 6 months in alcohol at ambient temperature and PdG concentrations even remained stable for up to 9 months of storage. FGCM concentrations of fecal samples kept at ambient temperature for up to 14 h post-defecation did not significantly differ compared to control samples frozen immediately after collection. These results provide the basis for the successful monitoring of the physiological status of orangutans living in remote natural settings, like those included in the Indonesian reintroduction programs.
authors: Faculty of Veterinary Science, Bogor Agricultural University, Bogor, Indonesia. tragulus@gmail.com.|Laboratory of Reproduction Division of Zoology, Research Center for Biology, Indonesian Institute of Sciences (LIPI), Jl. Raya Jakarta-Bogor Km. 46, Cibinong, 16911, Indonesia. tragulus@gmail.com.|Department of Anthropology, University of Zurich, Zurich, Switzerland. tragulus@gmail.com.
authors: Taufiq Purna
authors: TP
authors: Nugraha
authors: German Primate Centre, Endocrinology Laboratory, Göttingen, Germany.
authors: Michael
authors: M
authors: Heistermann
authors: Faculty of Veterinary Science, Bogor Agricultural University, Bogor, Indonesia.
authors: Muhammad
authors: M
authors: Agil
authors: Faculty of Veterinary Science, Bogor Agricultural University, Bogor, Indonesia.
authors: Bambang
authors: B
authors: Purwantara
authors: Faculty of Veterinary Science, Bogor Agricultural University, Bogor, Indonesia.
authors: Iman
authors: I
authors: Supriatna
authors: Laboratory of Physiology, Faculty of Veterinary Medicine, University of Syiah Kuala, Banda Aceh, Indonesia.
authors: Gholib
authors: G
authors: Gholib
authors: Department of Anthropology, University of Zurich, Zurich, Switzerland.
authors: Carel P
authors: CP
authors: van Schaik
authors: Department of Anthropology, University of Zurich, Zurich, Switzerland.
authors: Tony
authors: T
authors: Weingrill
mesh_terms: D000818:Animals; D005243:Feces / Q000737:chemistry*; D005260:Female; D005938:Glucocorticoids / Q000032:analysis* / Q000378:metabolism; D007214:Indonesia; D008297:Male; D010827:Physiology / Q000379:methods*; D057080:Pongo abelii / Q000502:physiology*; D011276:Pregnanediol / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism; D013048:Specimen Handling / Q000592:standards / Q000662:veterinary*
chemical_list: D005938:Glucocorticoids; C022270:pregnanediol-3 alpha-glucuronide; D011276:Pregnanediol
keywords: Fecal glucocorticoids; Hormone degradation; PdG; Pongo spp.; Sample storage