Effects of unsaturated fatty acids on torpor frequency and diet selection in Djungarian hamsters (Phodopus sungorus)

Abstract

Essential polyunsaturated fatty acids (PUFA) have been shown to play a beneficial role in hibernating mammals. High amounts of dietary PUFA led to an earlier hibernation onset, deeper and longer hibernation bouts and a higher proportion of hibernating animals in several species. In contrast, the relevance of dietary PUFA for daily heterotherms exhibiting only brief and shallow torpor bouts is less well studied. Therefore, diets differing in PUFA composition were used to examine the effects on the frequency of spontaneous daily torpor in Djungarian hamsters (Phodopus sungorus). In contrast to earlier studies, we were interested in whether the ratio of n-6 to n-3 PUFA affects torpor expression, and in comparison with a diet rich in monounsaturated fatty acids (MUFA). Although we found a positive effect on torpor frequency in hamsters fed a diet rich in n-6 PUFA compared with the groups fed diets either rich in n-3 PUFA or MUFA, the latter two groups did not show unusually low torpor frequencies. The results of the additional diet choice experiment indicated that hamsters in short photoperiod select food with only a slight excess of n-6 PUFA compared with n-3 PUFA (ratio of 1 to 1.5). However, there was no significant difference in torpor frequency between the diet choice group and hamsters fed on standard chow with a sevenfold excess of n-6 PUFA. In summary, the present data strongly indicate that the dietary composition of unsaturated fatty acids plays a minor role in the occurrence of spontaneous daily torpor in Djungarian hamsters.

Somatostatin receptor activation is involved in the control of daily torpor in a seasonal mammal

“…During the last 10 days, torpor was monitored by providing the hamsters with a small wooden nest box [7 ϫ 5 ϫ 5 cm (l ϫ h ϫ w) inner size] equipped with a small infrared thermometer (MLX90614ESF-BAA; Melexis Microelectronic Systems) for measurements of body surface temperature (T s). Ts values were stored every minute on a PC as previously described and validated (7). In addition to providing the torpor frequency, this setup allowed estimation of torpor bout duration by visual inspection of plotted raw data.…”

Human torpor: translating insights from nature into manned deep space expedition

“…Cell membranes undergo structural changes to maintain fluidity before the onset of torpor. Accumulating evidence suggests that poly‐unsaturated fatty acids (PUFAs) are involved in various torpor‐related physiological processes in hibernating species (Frank & Storey, 1995; Diedrich, Steinlechner & Scherbarth, 2014; Jefimow & Wojciechowski, 2014; Giroud et al ., 2018; Giroud et al ., 2019). Considering their positive role in neuroprotection, anti‐oxidation and anti‐inflammation (Shi et al ., 2015, 2016 a , b , 2018 b ), it is conceivable that PUFAs, particularly omega‐3 PUFAs, could be an important regulator of human torpor, at least in cell functions and tissue protection.…”

Regulation of Peroxisome Proliferator-Activated Receptor Pathway During Torpor in the Garden Dormouse, Eliomys quercinus

“…The presence of n-3 fatty acids can adversely affect a mammal's hibernation and this has been demonstrated to be true within a number of hibernating species (Frank et al, 2004;Ruf and Arnold, 2008;Diedrich et al, 2014). Differences in the ratio of n-6 to n-3 fatty acids within hibernators' diets modulates the deposition of adipose within depots as well as the total amount of adipose tissue within the animal (Frank et al, 1998), that can lead to downstream effects on a hibernator's ability to adapt to winter.…”