Title

Effects Of Storage Treatment On Fecal Steroid Hormone Concentrations Of A Rodent, The Cape Ground Squirrel (Xerus Inauris)

Keywords

Estrogen; Fecal steroids; Field storage; Progesterone; Rodents; Xerus

Abstract

Fecal steroid analysis is an increasingly common non-invasive technique used in both captive and field studies to measure an animal's approximate hormonal levels and corresponding physiological state. Fecal collection in the field necessitates storage and transportation methods that will prevent the degradation of hormonal metabolites by fecal bacteria. To determine the most stable and therefore preferred method of storage, 48 fecal samples were collected from six captive female Cape ground squirrels (Xerus inauris). Each sample was randomly divided into three sub-samples to be processed for storage through freezing, drying, or preservation in ethanol. Frozen samples were stored at -20 °C, dried-treated samples were desiccated in a conventional oven at 40 °C for 4 h, and alcohol-treated samples were preserved in 3 ml of 95% ethanol. Samples were stored for 330 days followed by enzyme immunoassay analysis (EIA) to determine their progestogen and estrone conjugate (E1C) concentrations. Validations were performed to establish that the progestogen and E1C assays accurately measure fecal progestogen and estrone conjugate concentrations and were sensitive enough to detect biologically meaningful differences in these steroid metabolite concentrations in female X. inauris. Validation results showed a significant difference in progestogen concentrations of gravid females compared to sub-adults and non-gravid females. There was also a significant difference in estrone conjugates between sub-adult and adult females. Duration of storage time did not affect progestogen or estrone metabolite concentrations after being frozen for 3 months. Storage treatment results showed no significant difference between frozen and dried samples, but a significant difference was found between frozen and ethanol samples in both progestogen and estrone conjugate concentrations demonstrating that drying feces provides a reliable method for long-term preservation of fecal steroid concentrations and is the better alternative when freezing is not a viable option. © 2006 Elsevier Inc. All rights reserved.

Publication Date

1-1-2007

Publication Title

General and Comparative Endocrinology

Volume

150

Issue

1

Number of Pages

1-11

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1016/j.ygcen.2006.06.010

Socpus ID

33845205798 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/33845205798

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