title: Circadian rhythm of salivary cortisol secretion in female zoo-kept African elephants (Loxodonta africana).
abstract: Salivary samples were collected over a 24-hr period from one group of six juvenile (7-12 years) and one group of three adult (24-25 years) African elephant females, Loxodonta africana, and the cortisol concentration was measured in unextracted samples by EIA. Samples were collected during May, June, and November 2012 (n = 147) using cotton swabs at 4-hr intervals from 20:00 to 20:00 of the next day (seven samples per animal in each trial). The animals are kept under standard zoo management: the herd is maintained in their indoor enclosures until 10:00 and then released into the outdoor enclosures until 21:00-21:30 (May/June) and 18:30-19:00 (November). No adult elephant bull was present at the zoo during this time. The results demonstrate a clear diurnal pattern of cortisol secretion with the lowest concentration observed at 20:00 (2.03 ± 0.08 ng/ml saliva) and the peak concentrations at 08:00 (5.26 ± 0.35 ng/ml saliva). Although the cortisol values were higher in the adult cows compared to the juvenile cows in the May-June period, the differences were not significant. However, the values obtained in November from the juvenile group were significantly higher (P < 0.05) than the concentrations measured in this group in June. In conclusion, salivary cortisol in zoo elephants follows a circadian rhythm (sleep-wake cycle) adapted to daily zoo husbandry routines.
authors.affiliation: Bioparc Valencia, Valencia, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: Casares
authors.affiliation: Departamento de Fisiología Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain.
authors.forename: Gema
authors.initials: G
authors.lastname: Silván
authors.affiliation: Bioparc Valencia, Valencia, Spain.
authors.forename: Maria Dolores
authors.initials: MD
authors.lastname: Carbonell
authors.affiliation: Bioparc Valencia, Valencia, Spain.
authors.forename: Cati
authors.initials: C
authors.lastname: Gerique
authors.affiliation: Departamento de Fisiología Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain.
authors.forename: Leticia
authors.initials: L
authors.lastname: Martinez-Fernandez
authors.affiliation: Departamento de Fisiología Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain.
authors.forename: Sara
authors.initials: S
authors.lastname: Cáceres
authors.affiliation: Departamento de Fisiología Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain.
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Illera
mesh_terms: D000818:Animals; D000836:Animals, Zoo / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology*; D004606:Elephants / Q000502:physiology*; D005260:Female; D006854:Hydrocortisone / Q000378:metabolism*; D012463:Saliva / Q000378:metabolism*
chemical_list: D006854:Hydrocortisone
keywords: adrenal activity; glucocorticoids; non-invasive monitoring; saliva; welfare