Thermal physiology and energetics in male desert hamsters (Phodopus roborovskii) during cold acclimation

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 mlO(2) 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.

Serum Leptin, Energy Budget, and Thermogenesis in Striped Hamsters Exposed to Consecutive Decreases in Ambient Temperatures

“…For example, the small and large intestines were heavier by 26% and 17%, respectively, at Ϫ23ЊC than those at 23ЊC, indicating adaptive responses of the digestive tract's morphology to increased food intake. A cold-stimulated hyperphagia has been also observed in many other rodents, including Brant's voles (Li and Wang 2005a), Mongolian gerbils (Li and Wang 2005b), and desert hamsters Phodopus roborovskii (Chi and Wang 2011). Inconsistently, Siberian hamsters do not show an elevation of food intake in cold winters or winterlike conditions (Klingenspor et al 2000).…”

Limits to sustained energy intake. XVIII. Energy intake and reproductive output during lactation in Swiss mice raising small litters

“…Here, RQ was assumed to be 0.85 (Withers, 1977;Chi and Wang, 2011 ) (Weir, 1949;Speakman, 1999;Johnson et al, 2001a). All measurements were made between 10:00h and 17:00h.…”

High body weight associated with impaired nonshivering thermogenesis but improved glucose tolerance in Mongolian gerbils (Meriones unguiculatus)

“…In contrast to BAT thermogenesis, RMR of gerbils slightly went up with increasing body mass. Rodent species from arid and semiarid environments which have low values of RMR show high NST values (Haim and Izhaki, 1993;Chi and Wang, 2011). According to these results, we suggest that slightly higher RMR is a compensation for the low BAT thermogenesis in HBW gerbils.…”