Abstract
This study was carried out to determine heart rate (HR) values, including diurnal, seasonal, and sex patterns, in the African giant rat (Cricetomys gambianus, Waterhouse). HR was measured using stethoscope in grip-restrained African giant rats of either sex (103 bucks and 98 does), live-trapped from a tropical Savannah, and caged individually in the laboratory during the harmattan (cold-dry), hot-dry, and rainy seasons over a 3-year period. The HR fluctuated between 90 and 210 beats per minute (bpm) throughout the study period. Diurnal changes in HR (mean ± SEM) during the hot-dry and rainy seasons were nonsignificant (P > 0.05), but the morning and afternoon values differed (P < 0.01) during the cold-dry season. The HR varied (P < 0.05) among seasons, with peak, nadir, and moderate values recorded during the cold-dry (165.8 ± 0.51 bpm), hot-dry (153.1 ± 0.74 bpm), and rainy (163.4 ± 0.70 bpm) seasons, respectively. Mean HR of bucks was lower than that of does during the cold-dry (P < 0.0001) and hot-dry (P < 0.01) seasons, but sex difference during the rainy season was insignificant (P > 0.05). Overall, mean HR was lower (P < 0.0001) in bucks (158.8 ± 0.53 bpm) than in does (164.8 ± 0.53 bpm). In conclusion, values of HR in African giant rats are shown for the first time. Season, sex, and daytime influenced the HR, and should be considered during clinical evaluations of the rats.
Highlights
The relationship between the animal and its environment is best studied based on the knowledge of the physiological constants, maintained by self-regulating processes of the animal, such as body temperature, respiratory rate, and heart rate (HR) (Ayo et al 2014)
The results showed individual fluctuations in values of the HR over a 3-year period in buck and doe AGRs, during the cold-dry, hot-dry, and rainy seasons, in the morning, afternoon, and evening
The results demonstrated the importance of generating data across seasons and during the hours of the day in both sexes before concluding on baseline/reference values
Summary
The relationship between the animal and its environment is best studied based on the knowledge of the physiological constants, maintained by self-regulating processes of the animal, such as body temperature, respiratory rate, and heart rate (HR) (Ayo et al 2014). The paraventricular nucleus in the hypothalamus is an established center of cardiovascular control in rats (Feetham and Barrett-Jolley 2014), the HR may be altered rapidly due to inputs from environmental cues (zeitgebers), such as ambient temperature and photoperiod, psychosocial factors like housing, or due to intense activity, including feeding, by the animal (van den Buuse 1999; Swoap et al 2004; Azar et al 2011; Carnevali and Sgoifo 2014). Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
