Daily rhythms of physiological parameters in the dromedary camel under natural and laboratory conditions

Journal Article

Abdoun, Khalid A. . 2016

• نوع عمل المنشور: Publication
• رابط المنشور على الويب: Daily rhythms of physiological parameters in the dromedary camel under natural and laboratory conditions
• الوسوم: Core body temperature Circadian rhythm Camelus dromedarius Heat exposure Nycthemeral rhythm Rhythm r
• المجلة \ الصحيفة: Research in Veterinary Science
• رقم الإصدار السنوي: 107
• الصفحات: 273-277

مستخلص المنشور

Camels arewell adapted to hot arid environments and can contribute significantly to the economy of developing
countries in arid regions of the world. Full understanding of the physiology of camels requires understanding of
the internal temporal order of the body, as reflected in daily or circadian rhythms. In the current study,we investigated
the daily rhythmicity of 20 physiological variables in camels exposed to natural oscillations of ambient
temperature in a desert environment and compared the daily temporal courses of the variables. We also studied
the rhythmof core body temperature under experimental conditions with constant ambient temperature in the
presence and absence of a light-dark cycle. The obtained results indicated that different physiological variables
exhibit different degrees of daily rhythmicity and reach their daily peaks at different times of the day, starting
with plasma cholesterol, which peaks 24 min after midnight, and ending with plasma calcium, which peaks
3 h before midnight. Furthermore, the rhythmof core body temperature persisted in the absence of environmental
rhythmicity, thus confirming its endogenous nature. The observed delay in the acrophase of core body temperature
rhythm under constant conditions suggests that the circadian period is longer than 24 h. Further
studies with more refined experimental manipulation of different variables are needed to fully elucidate the
causal network of circadian rhythms in dromedary camels.