Rumination shows a nocturnal rhythmic pattern in day-active ruminants. Although feeding has been shown to quantitatively modulate rumination, it is not clear yet if feeding rhythm plays a causal role in rumination rhythm. The present study was carried out to determine whether the daily rhythm of rumination in goats under natural environmental conditions is food-dependent or not, and whether it is modulated by the season.
View Article and Find Full Text PDFThe 'first night effect' (FNE) is a well-known phenomenon in polysomnographic (PSG) sleep studies, resulting in significant variations in the macrostructure of wakefulness and sleep states, particularly between the initial and subsequent sleep recording sessions. The FNE phenomenon during sleep has been studied in various species, revealing complex variations between several sessions of sleep recording. The present study used a non-invasive PSG method to examine differences between various vigilance states in four adult female dromedary camels during 4 consecutive nights and days of sleep recording.
View Article and Find Full Text PDFStudy Objectives: To investigate sleep patterns in the camel by combining behavioral and polysomnography (PSG) methods.
Methods: A noninvasive PSG study was conducted over four nights on four animals. Additionally, video recordings were used to monitor the sleep behaviors associated with different vigilance states.
In the dromedary camel, a well-adapted desert mammal, daily ambient temperature (T)-cycles have been shown to synchronize the central circadian clock. Such entrainment has been demonstrated by examining two circadian outputs, body temperature and melatonin rhythms. Locomotor activity (LA), another circadian output not yet investigated in the camel, may provide further information on such specific entrainment.
View Article and Find Full Text PDFIn desert areas, mammals such as camel and goat are exposed to harsh environmental conditions. The ambient temperature (Ta) cycles have been shown to entrain the circadian clock in the camel. In the present work, we assumed that, in the goat living in a desert biotope, Ta cycles would have the same synchronizing effect on the central clock.
View Article and Find Full Text PDFThis article presents data on the effect of plasmapheresis on clinical, haematological and biochemical parameters in horses following exercise and after a plasmapheresis session. This blood filtration technique was realised on six jumping horses (plasmapheresis group) that underwent three consecutive days of graded physical exercise. The control group (n = 6) went through the same exercise but was not subjected to the plasmapheresis session.
View Article and Find Full Text PDFTo evaluate the effect of plasmapheresis on clinical, hematological, and biochemical parameters after exercise, a plasmapheresis session was realized on six jumping horses (plasmapheresis group) that underwent three consecutive days of physical graded exercise. The control group (n = 6) went through the same exercise but not subjected to the plasmapheresis session. Seventeen milliliters of plasma/kg of body weight was harvested from each horse.
View Article and Find Full Text PDFThe dromedary camel (Camelus dromedarius) is a desert mammal whose cycles in reproductive activity ensure that the offspring's birth and weaning coincide with periods of abundant food resources and favorable climate conditions. In this study, we assessed whether kisspeptin (Kp) and arginine-phenylalanine (RF)-amide related peptide-3 (RFRP-3), two hypothalamic peptides known to regulate the mammalian hypothalamo-pituitary gonadal axis, may be involved in the seasonal control of camel's reproduction. Using specific antibodies and riboprobes, we found that Kp neurons are present in the preoptic area (POA), suprachiasmatic (SCN), and arcuate (ARC) nuclei, and that RFRP-3 neurons are present in the paraventricular (PVN), dorsomedial (DMH), and ventromedial (VMH) hypothalamic nuclei.
View Article and Find Full Text PDFTo examine a possible control of reproductive seasonality by melatonin, continual-release subcutaneous melatonin implants were inserted 4.5 months before the natural breeding season (October-April) into female camels (Melatonin-treated group). The animals were exposed to an artificial long photoperiod (16L:8D) for 41 days prior to implant placement to facilitate receptivity to the short-day signal that is expected with melatonin implants.
View Article and Find Full Text PDFIn mammals, biological rhythms are driven by a master circadian clock located in the suprachiasmatic nucleus (SCN) of the hypothalamus. Recently, we have demonstrated that in the camel, the daily cycle of environmental temperature is able to entrain the master clock. This raises several questions about the structure and function of the SCN in this species.
View Article and Find Full Text PDFIn 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.
View Article and Find Full Text PDFAm J Physiol Regul Integr Comp Physiol
June 2013
In mammals the light-dark (LD) cycle is known to be the major cue to synchronize the circadian clock. In arid and desert areas, the camel (Camelus dromedarius) is exposed to extreme environmental conditions. Since wide oscillations of ambient temperature (Ta) are a major factor in this environment, we wondered whether cyclic Ta fluctuations might contribute to synchronization of circadian rhythms.
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