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Non-invasive cortisol measurements as indicators of physiological stress responses in guinea pigs

Non-invasive measurements of glucocorticoid (GC) concentrations, including cortisol and corticosterone, serve as reliable indicators of adrenocortical activities and physiological stress loads in a variety of species. As an alternative to invasive analyses based on plasma, GC concentrations in saliv...

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Autores principales: Nemeth, Matthias, Pschernig, Elisabeth, Wallner, Bernard, Millesi, Eva
Formato: Online Artículo Texto
Lenguaje:English
Publicado: PeerJ Inc. 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4734438/
https://www.ncbi.nlm.nih.gov/pubmed/26839750
http://dx.doi.org/10.7717/peerj.1590
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author Nemeth, Matthias
Pschernig, Elisabeth
Wallner, Bernard
Millesi, Eva
author_facet Nemeth, Matthias
Pschernig, Elisabeth
Wallner, Bernard
Millesi, Eva
author_sort Nemeth, Matthias
collection PubMed
description Non-invasive measurements of glucocorticoid (GC) concentrations, including cortisol and corticosterone, serve as reliable indicators of adrenocortical activities and physiological stress loads in a variety of species. As an alternative to invasive analyses based on plasma, GC concentrations in saliva still represent single-point-of-time measurements, suitable for studying short-term or acute stress responses, whereas fecal GC metabolites (FGMs) reflect overall stress loads and stress responses after a species-specific time frame in the long-term. In our study species, the domestic guinea pig, GC measurements are commonly used to indicate stress responses to different environmental conditions, but the biological relevance of non-invasive measurements is widely unknown. We therefore established an experimental protocol based on the animals’ natural stress responses to different environmental conditions and compared GC levels in plasma, saliva, and fecal samples during non-stressful social isolations and stressful two-hour social confrontations with unfamiliar individuals. Plasma and saliva cortisol concentrations were significantly increased directly after the social confrontations, and plasma and saliva cortisol levels were strongly correlated. This demonstrates a high biological relevance of GC measurements in saliva. FGM levels measured 20 h afterwards, representing the reported mean gut passage time based on physiological validations, revealed that the overall stress load was not affected by the confrontations, but also no relations to plasma cortisol levels were detected. We therefore measured FGMs in two-hour intervals for 24 h after another social confrontation and detected significantly increased levels after four to twelve hours, reaching peak concentrations already after six hours. Our findings confirm that non-invasive GC measurements in guinea pigs are highly biologically relevant in indicating physiological stress responses compared to circulating levels in plasma in the short- and long-term. Our approach also underlines the importance of detailed investigations on how to use and interpret non-invasive measurements, including the determination of appropriate time points for sample collections.
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spelling pubmed-47344382016-02-02 Non-invasive cortisol measurements as indicators of physiological stress responses in guinea pigs Nemeth, Matthias Pschernig, Elisabeth Wallner, Bernard Millesi, Eva PeerJ Animal Behavior Non-invasive measurements of glucocorticoid (GC) concentrations, including cortisol and corticosterone, serve as reliable indicators of adrenocortical activities and physiological stress loads in a variety of species. As an alternative to invasive analyses based on plasma, GC concentrations in saliva still represent single-point-of-time measurements, suitable for studying short-term or acute stress responses, whereas fecal GC metabolites (FGMs) reflect overall stress loads and stress responses after a species-specific time frame in the long-term. In our study species, the domestic guinea pig, GC measurements are commonly used to indicate stress responses to different environmental conditions, but the biological relevance of non-invasive measurements is widely unknown. We therefore established an experimental protocol based on the animals’ natural stress responses to different environmental conditions and compared GC levels in plasma, saliva, and fecal samples during non-stressful social isolations and stressful two-hour social confrontations with unfamiliar individuals. Plasma and saliva cortisol concentrations were significantly increased directly after the social confrontations, and plasma and saliva cortisol levels were strongly correlated. This demonstrates a high biological relevance of GC measurements in saliva. FGM levels measured 20 h afterwards, representing the reported mean gut passage time based on physiological validations, revealed that the overall stress load was not affected by the confrontations, but also no relations to plasma cortisol levels were detected. We therefore measured FGMs in two-hour intervals for 24 h after another social confrontation and detected significantly increased levels after four to twelve hours, reaching peak concentrations already after six hours. Our findings confirm that non-invasive GC measurements in guinea pigs are highly biologically relevant in indicating physiological stress responses compared to circulating levels in plasma in the short- and long-term. Our approach also underlines the importance of detailed investigations on how to use and interpret non-invasive measurements, including the determination of appropriate time points for sample collections. PeerJ Inc. 2016-01-18 /pmc/articles/PMC4734438/ /pubmed/26839750 http://dx.doi.org/10.7717/peerj.1590 Text en ©2016 Nemeth et al. http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ) and either DOI or URL of the article must be cited.
spellingShingle Animal Behavior
Nemeth, Matthias
Pschernig, Elisabeth
Wallner, Bernard
Millesi, Eva
Non-invasive cortisol measurements as indicators of physiological stress responses in guinea pigs
title Non-invasive cortisol measurements as indicators of physiological stress responses in guinea pigs
title_full Non-invasive cortisol measurements as indicators of physiological stress responses in guinea pigs
title_fullStr Non-invasive cortisol measurements as indicators of physiological stress responses in guinea pigs
title_full_unstemmed Non-invasive cortisol measurements as indicators of physiological stress responses in guinea pigs
title_short Non-invasive cortisol measurements as indicators of physiological stress responses in guinea pigs
title_sort non-invasive cortisol measurements as indicators of physiological stress responses in guinea pigs
topic Animal Behavior
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4734438/
https://www.ncbi.nlm.nih.gov/pubmed/26839750
http://dx.doi.org/10.7717/peerj.1590
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