Fecal cortisol radioimmunoassay to monitor adrenal gland activity in the bottlenose dolphin (Tursiops truncatus) under human care

Abstract

Fecal glucocorticoid measurement is an important noninvasive tool to monitor animal health. A radioimmunoassay (RIA) method was developed to measure fecal cortisol in bottlenose dolphins under human care. The method was used to measure baseline hormone levels and evaluate the adrenal response to environmental challenges in a small number of individual dolphins. The method was validated by precision and accuracy tests and by comparison with liquid chromatography‐mass spectrometry (LC‐MS). The parallelism test suggested few matrix interferences. The assay showed a good degree of precision within assay (CV = 5.4%) and between assays (CV = 4.1%). The RIA significantly correlated with the LC‐MS method (r = 0.838, P < 0.01). The recovery test and the comparison between RIA and LC‐MS suggested that the RIA slightly underestimates fecal cortisol concentrations, although the degree of accuracy was good. This study established that bottlenose dolphins excrete appreciable amounts of fecal cortisol (healthy subjects: 0.2–9.5 ng/g). Therefore, chronic HPA axis activation may be monitored in fecal samples by immunoassays after validating a suitable extraction protocol. The RIA could discriminate conditions of stimulation (pregnancy, parturition, isolation, transportation) and inhibition (diazepam administration) of the HPA axis and may, therefore, be useful for monitoring dolphin well‐being.

Circulating and Excreted Corticosteroids and Metabolites, Hematological, and Serum Chemistry Parameters in the Killer Whale (Orcinus orca) Before and After a Stress Response

“…Further, Champagne et al (2018) observed an increase in fecal cortisol metabolites at 4.5 h after initiation of the stressors. Biancani et al (2017) did not detect a rise in FGCMs after a prolonged transport stressor, with sampling at 1, 24, and 27 h post-transport, supporting the premise that the rise in FGCMs in their study was missed because it occurs within a 1-24 h period post-stressor, and possibly between 4 and 8 h post-stressor. An increased sampling frequency and successful fecal collection may have increased our chances of detecting a change, if indeed one was present to detect.…”

“…Liquid chromatographymass spectrometry (LCMS) analysis of bottlenose dolphin feces revealed that native cortisol but not corticosterone was present, suggesting that antibodies that react with cortisol are sufficient for quantifying cortisol in bottlenose dolphin feces (Biancani et al, 2017). However, Biancani et al (2017) did not fully examine Abs eos #F 1,68 = 8.2, P = 0.006 mR 2 = 0.10, mP = 0.003…”

“…Antibodies used for GC measurements may cross-react with other steroid hormones and metabolites, which can lead to inaccurate quantification of FGCMs (Ganswindt et al, 2003;Hunt et al, 2006;Goymann, 2012). Liquid chromatographymass spectrometry (LCMS) analysis of bottlenose dolphin feces revealed that native cortisol but not corticosterone was present, suggesting that antibodies that react with cortisol are sufficient for quantifying cortisol in bottlenose dolphin feces (Biancani et al, 2017). However, Biancani et al (2017) did not fully examine Abs eos #F 1,68 = 8.2, P = 0.006 mR 2 = 0.10, mP = 0.003…”

Effect of relative humidity at either acute or chronic moderate temperature on growth performance and droppings' corticosterone metabolites of broilers

“…Previous studies have shown that the total amount of droppings' corticosterone metabolites were positively correlated with plasma corticosterone, indicating that droppings' corticosterone metabolites could also be used to diagnose stress response (Bradely and Holmes 1971;Culbert and Wells 1975;Teskey-Gerstl et al 2000b;Dehnhard et al 2001). And it has been already used to investigate questions in the fields of "stress and animal welfare, reproductive, physiology, and behavioral ecology" (Turriani et al 2016;Yarnell et al 2016;Biancani et al 2017;Cao et al 2017;Webster et al 2017;Cinque et al 2018;Wolf et al 2018), such as fighting against spotted hyenas (Goymann et al 1999), drought or social stress on African elephants (Foley et al 2001), catching stress on laying hens (Fraisse and Cockrem 2006), mercury exposure to tern stress (Herring et al 2012), and heat stress on broilers ( Su et al 2014a/b? ).…”

Analysis of non-conjugated steroids in water using paper spray mass spectrometry

“…Radioimmunoassay (RIA) is the most common analytical method used to measure steroids with good sensitivity and reproducibility 18,19 . RIA is gradually being replaced by enzyme-linked immunosorbent assays (ELISA) because of legislation relating to laboratory waste 20,21 .…”