title: Daily regulation of body temperature rhythm in the camel (Camelus dromedarius) exposed to experimental desert conditions.
abstract: In the present work, we have studied daily rhythmicity of body temperature (Tb) in Arabian camels challenged with daily heat, combined or not with dehydration. We confirm that Arabian camels use heterothermy to reduce heat gain coupled with evaporative heat loss during the day. Here, we also demonstrate that this mechanism is more complex than previously reported, because it is characterized by a daily alternation (probably of circadian origin) of two periods of poikilothermy and homeothermy. We also show that dehydration induced a decrease in food intake plays a role in this process. Together, these findings highlight that adaptive heterothermy in the Arabian camel varies across the diurnal light-dark cycle and is modulated by timing of daily heat and degrees of water restriction and associated reduction of food intake. The changed phase relationship between the light-dark cycle and the Tb rhythm observed during the dehydration process points to a possible mechanism of internal desynchronization during the process of adaptation to desert environment. During these experimental conditions mimicking the desert environment, it will be possible in the future to determine if induced high-amplitude ambient temperature (Ta) rhythms are able to compete with the zeitgeber effect of the light-dark cycle.
authors.affiliation: Department of Neurobiology of Rhythms, CNRS UPR 3212, Institute for Cellular and Integrative Neurosciences, University of Strasbourg, Strasbourg, France Comparative Anatomy Unit (URAC CNRST 49), Hassan II Agronomy and Veterinary Institute, Rabat, Morocco.
authors.forename: Hanan
authors.initials: H
authors.lastname: Bouâouda
authors.affiliation: Comparative Anatomy Unit (URAC CNRST 49), Hassan II Agronomy and Veterinary Institute, Rabat, Morocco.
authors.forename: Mohamed R
authors.initials: MR
authors.lastname: Achâaban
authors.affiliation: Comparative Anatomy Unit (URAC CNRST 49), Hassan II Agronomy and Veterinary Institute, Rabat, Morocco.
authors.forename: Mohammed
authors.initials: M
authors.lastname: Ouassat
authors.affiliation: Comparative Anatomy Unit (URAC CNRST 49), Hassan II Agronomy and Veterinary Institute, Rabat, Morocco.
authors.forename: Mohammed
authors.initials: M
authors.lastname: Oukassou
authors.affiliation: Medecine and Surgical Unit of domestic animals, Hassan II Agronomy and Veterinary Institute, Rabat, Morocco.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Piro
authors.affiliation: Department of Neurobiology of Rhythms, CNRS UPR 3212, Institute for Cellular and Integrative Neurosciences, University of Strasbourg, Strasbourg, France.
authors.forename: Etienne
authors.initials: E
authors.lastname: Challet
authors.affiliation: Comparative Anatomy Unit (URAC CNRST 49), Hassan II Agronomy and Veterinary Institute, Rabat, Morocco.
authors.forename: Khalid
authors.initials: K
authors.lastname: El Allali
authors.affiliation: Department of Neurobiology of Rhythms, CNRS UPR 3212, Institute for Cellular and Integrative Neurosciences, University of Strasbourg, Strasbourg, France.
authors.forename: Paul
authors.initials: P
authors.lastname: Pévet
keywords: Adaptive heterothermy; body temperature rhythm; camel; circadian clock; dehydration; food decrease; heat stress