Using an on-site laboratory for fecal steroid analysis in wild white-faced capuchins

Beehner, Jacinta C.; Alfaro, José A.; Allen, Cloe; Benítez, Marcela E.; Bergman, Thore J.; Buehler, Margaret S.; Carrera, Sofia C.; Chester, Emily M.; Deschner, Tobias; Fuentes, Alexander; Gault, Colleen M.; Godoy, Irene; Jack, Katharine M.; Kim, Justin D.; Kolinski, Lev; Kulick, Nelle K.; Losch, Teera; Ordóñez, Juan C.; Perry, Seymour; Pinto, Fernando; Reilly, Olivia T.; Johnson, Elizabeth Tinsley; Wasserman, Michael D.

doi:10.1016/j.ygcen.2022.114109

Cited by 1 publication

(4 citation statements)

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“…Running within-and between-assay controls we found that the EIA was sufficiently precise within the same assay plates; however, there was elevated variation for the between-assay controls that consisted of sample pools but not in the standard controls provided by the manufacturer. This pattern of results highlights the importance to include sample pool controls rather than exclusively relying on standard controls as those could potentially underestimate within-and between-assay variation (Beehner et al, 2022). Variation between EIA plates can be influenced by multiple factors such as changes in temperature, variation in performance while using the plate, and plate batch.…”

Section: Discussionmentioning

confidence: 99%

“…We calculated the expected concentration as the sum of the pooled sample and the cortisol standard. We divided the measured concentration by the expected concentration and multiplied the result by 100 as described by Beehner et al (2022).…”

Section: Methodsmentioning

confidence: 99%

“…Climatic seasonality is often correlated with variation in GC concentrations (e.g., Beehner et al, 2022; Carnegie et al, 2011). We collected rain data at the field site using a commercial weather station which was positioned approximately 2.5 m above the ground on a plane surface with no canopy coverage.…”

Section: Methodsmentioning

confidence: 99%

“…Most commercial kits are designed for quantification of GC in human blood or saliva; however, some of them have been shown to be suitable for samples of other species and matrices (e.g., Ordóñez‐Gómez et al, 2016; Rangel‐Negrín et al, 2014; Weingrill et al, 2004). When using commercial kits it is paramount to subject them to analytical validation for the study species and sample matrix including: (1) parallelism between a standard calibration curve and the sample extracts to investigate the dynamics of antibody binding and exclude the presence of a systematic inference by the extract matrix (Selby, 1999): (2) accuracy of analysis (i.e., quantification of a known standard in the presence of sample matrix); and (3) precision of analysis (i.e., within‐ and between‐assay controls; Beehner et al, 2022; Buchanan & Goldsmith, 2004). Another challenge for immunological analysis is the presence of a diverse bacterial community in fecal samples that causes degradation of GC molecules, leading to unknown types and amounts of fecal GC metabolites (fGCM) and low amounts of the original target molecule (Goymann, 2012).…”

Section: Introductionmentioning

confidence: 99%

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Analytical and biological validation of a noninvasive measurement of glucocorticoid metabolites in feces of Geoffroy's spider monkeys (Ateles geoffroyi)

Damm,

Aureli,

Rangel‐Negrín

et al. 2024

American J Primatol

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We report on an analytical and biological validation of a commercial cortisol enzyme immunoassay (EIA) to measure glucocorticoids (GC) in feces of Geoffroy's spider monkeys (Ateles geoffroyi). Validation of endocrinological methods for each sample matrix and study species is crucial to establish that the methods produce reliable results. For the analytical validation of the EIA, we assessed parallelism, accuracy, and precision. We carried out a biological validation based on three well‐studied GC patterns with the following predictions: (1) increased fecal GC metabolite (fGCM) concentrations after veterinary intervention; (2) increased fGCM concentrations during early morning hours; and (3) higher fGCM concentrations during gestation than in other female reproductive states. For the first prediction, we sampled feces of two zoo‐housed females 2 days before, the day of, and 2 days after a veterinary intervention. For the second prediction, we analyzed 284 fecal samples collected from 12 wild males using a linear mixed model (LMM). For the third prediction, we analyzed 269 fecal samples of eight wild females using an LMM. Analytical validation revealed that the EIA showed parallelism, was accurate, and precise within each assay. However, there was elevated variation in between‐assay precision. The biological validation supported all predictions: (1) the two zoo‐housed females showed a substantial increase in fGCM concentrations 2.5 and 11 h after veterinary intervention; (2) there was a negative effect of sample collection time on fGCM concentrations (i.e., higher concentrations during early morning); (3) gestating females had significantly higher fGCM concentrations than lactating females. Thus, we analytically validated the commercial EIA and, despite between‐assay variation, we were able to find three biologically relevant GC signals in captive and wild settings, and in males and females. We are therefore confident that the method can be used to noninvasively address behavioral endocrinology questions in Geoffroy's spider monkeys.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%