Thermal physiology and energetics in male desert hamsters (<Emphasis Type="Italic">Phodopus roborovskii</Emphasis>) during cold acclimation |
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Authors: | Qing-Sheng Chi De-Hua Wang |
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Institution: | (1) State Key Laboratory of Integrated Management for Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China;(2) Graduate University of Chinese Academy of Sciences, Beijing, 100049, China;(3) Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang, Beijing, 100101, People’s Republic of China |
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Abstract: | The adjustments in thermal physiology and energetics were investigated in male desert hamsters (Phodopus roborovskii) which were acclimated to 5°C for 4 weeks. Mean core body temperature in cold acclimated animals decreased by 0.21°C compared
with controls. Further analysis revealed that the decrease mainly occurred in the scotophase, while in the photophase core
body temperature remained constant during the whole cold acclimation. Thermogenic capacity, represented by resting metabolic
rate and nonshivering thermogenesis increased in cold acclimated hamsters from initial values of 1.38 ± 0.05 and 5.32 ± 0.30
to 1.77 ± 0.08 and 8.79 ± 0.31 mlO2 g−1 h−1, respectively. After cold acclimation, desert hamsters maintained a relative stable body mass of 21.7 ± 0.1 g very similar
to the controls kept at 23°C (21.8 ± 0.1 g). The mean values of food intake and digestible energy (metabolisable energy) in
cold acclimated hamsters were 5.3 ± 0.1 g day−1 and 76.3 ± 0.9 kJ day−1 (74.8 ± 0.9), respectively, which were significantly elevated by 76.7 and 80.4% compared to that in control group. The apparent
digestibility was 81.0 ± 0.3% in cold acclimated animals which was also higher than the 79.7 ± 0.2% observed in controls.
This increase corresponded with adaptive adjustments in morphology of digestive tracts with 20.2 and 36.8% increases in total
length and wet mass, respectively. Body fat mass and serum leptin levels in cold acclimated hamsters decreased by 40.7 and
67.1%, respectively. The wheel running turns and the onset of wheel running remained unchanged. Our study indicated that desert
hamsters remained very active during cold acclimation and displayed adaptive changes in thermal physiology and energy metabolism,
such as enhanced thermogenic and energy processing capacities. |
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