Salivary Cortisol Reaction Norms in Zoo-Housed Great Apes: Diurnal Slopes and Intercepts as Indicators of Stress Response Quality
Monitoring changes in cortisol levels is a widespread tool for measuring individuals’ stress responses. However, an acute increase in cortisol levels does not necessarily denote an individual in distress, as increases in cortisol can be elicited by all factors that signal the need to mobilize energy...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-02-01
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| Series: | Animals |
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| Online Access: | https://www.mdpi.com/2076-2615/12/4/522 |
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| author | Verena Behringer Jeroen M. G. Stevens Ruth Sonnweber |
| author_facet | Verena Behringer Jeroen M. G. Stevens Ruth Sonnweber |
| author_sort | Verena Behringer |
| collection | DOAJ |
| description | Monitoring changes in cortisol levels is a widespread tool for measuring individuals’ stress responses. However, an acute increase in cortisol levels does not necessarily denote an individual in distress, as increases in cortisol can be elicited by all factors that signal the need to mobilize energy. Nor are low levels of cortisol indicative for a relaxed, healthy individual. Therefore, a more fine-grained description of cortisol patterns is warranted in order to distinguish between cortisol fluctuations associated with different stress response qualities. In most species, cortisol shows a distinct diurnal pattern. Using a reaction norm approach, cortisol levels across the day can be described by the two regression coefficients: the intercept and the slope of the curve. We measured immunoreactive salivary cortisol in three zoo-housed ape species under three conditions (routine days, enrichment days, and after the move to a new house). We examined salivary cortisol intercepts (SCI) and salivary cortisol slopes (SCS) of the diurnal curves. SCI and SCS were independent from each other. SCI was highest on enrichment days and lowest on routine days. SCS was steep on routine days and blunted after the move. Only SCI was species-specific. Our study provides evidence that combining SCI and SCS measures allows us to differentiate between types of stress responses, thereby constituting a useful tool for welfare assessment. |
| first_indexed | 2024-03-09T22:47:07Z |
| format | Article |
| id | doaj.art-16b9f9c566dd403a86357413eb08b950 |
| institution | Directory Open Access Journal |
| issn | 2076-2615 |
| language | English |
| last_indexed | 2024-03-09T22:47:07Z |
| publishDate | 2022-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Animals |
| spelling | doaj.art-16b9f9c566dd403a86357413eb08b9502023-11-23T18:26:33ZengMDPI AGAnimals2076-26152022-02-0112452210.3390/ani12040522Salivary Cortisol Reaction Norms in Zoo-Housed Great Apes: Diurnal Slopes and Intercepts as Indicators of Stress Response QualityVerena Behringer0Jeroen M. G. Stevens1Ruth Sonnweber2Endocrinology Laboratory, German Primate Center, Leibniz Institute for Primate Research, Kellnerweg 4, 37077 Göttingen, GermanyBehavioral Ecology and Ecophysiology, Department of Biology, University of Antwerp, Universiteitsplein 1, 2610 Antwerp, BelgiumDepartment of Behavioral and Cognitive Biology, University of Vienna, Djerassiplatz 1, 1030 Vienna, AustriaMonitoring changes in cortisol levels is a widespread tool for measuring individuals’ stress responses. However, an acute increase in cortisol levels does not necessarily denote an individual in distress, as increases in cortisol can be elicited by all factors that signal the need to mobilize energy. Nor are low levels of cortisol indicative for a relaxed, healthy individual. Therefore, a more fine-grained description of cortisol patterns is warranted in order to distinguish between cortisol fluctuations associated with different stress response qualities. In most species, cortisol shows a distinct diurnal pattern. Using a reaction norm approach, cortisol levels across the day can be described by the two regression coefficients: the intercept and the slope of the curve. We measured immunoreactive salivary cortisol in three zoo-housed ape species under three conditions (routine days, enrichment days, and after the move to a new house). We examined salivary cortisol intercepts (SCI) and salivary cortisol slopes (SCS) of the diurnal curves. SCI and SCS were independent from each other. SCI was highest on enrichment days and lowest on routine days. SCS was steep on routine days and blunted after the move. Only SCI was species-specific. Our study provides evidence that combining SCI and SCS measures allows us to differentiate between types of stress responses, thereby constituting a useful tool for welfare assessment.https://www.mdpi.com/2076-2615/12/4/522animal welfarebonoboorangutangorillaenrichmentnon-invasive monitoring |
| spellingShingle | Verena Behringer Jeroen M. G. Stevens Ruth Sonnweber Salivary Cortisol Reaction Norms in Zoo-Housed Great Apes: Diurnal Slopes and Intercepts as Indicators of Stress Response Quality Animals animal welfare bonobo orangutan gorilla enrichment non-invasive monitoring |
| title | Salivary Cortisol Reaction Norms in Zoo-Housed Great Apes: Diurnal Slopes and Intercepts as Indicators of Stress Response Quality |
| title_full | Salivary Cortisol Reaction Norms in Zoo-Housed Great Apes: Diurnal Slopes and Intercepts as Indicators of Stress Response Quality |
| title_fullStr | Salivary Cortisol Reaction Norms in Zoo-Housed Great Apes: Diurnal Slopes and Intercepts as Indicators of Stress Response Quality |
| title_full_unstemmed | Salivary Cortisol Reaction Norms in Zoo-Housed Great Apes: Diurnal Slopes and Intercepts as Indicators of Stress Response Quality |
| title_short | Salivary Cortisol Reaction Norms in Zoo-Housed Great Apes: Diurnal Slopes and Intercepts as Indicators of Stress Response Quality |
| title_sort | salivary cortisol reaction norms in zoo housed great apes diurnal slopes and intercepts as indicators of stress response quality |
| topic | animal welfare bonobo orangutan gorilla enrichment non-invasive monitoring |
| url | https://www.mdpi.com/2076-2615/12/4/522 |
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