Energy budgets of captive Chinese pangolins ().

The Chinese pangolin is an endangered species, and conservation and captive rescue are important conservation measures. This requires reliable information on nutritional energy requirements and expenditure characteristics. However, we lack sufficient knowledge of their energy physiology to determine their energy requirements for maintenance and growth.

Surviving winter on the Qinghai-Tibetan Plateau: Pikas suppress energy demands and exploit yak feces to survive winter.

The Qinghai-Tibetan Plateau, with low precipitation, low oxygen partial pressure, and temperatures routinely dropping below -30 °C in winter, presents several physiological challenges to its fauna. Yet it is home to many endemic mammalian species, including the plateau pika (). How these small animals that are incapable of hibernation survive the winter is an enigma.

The responses of metabolic rate and neuropeptides to food deprivation in striped hamsters (Cricetulus barabensis) with different basal metabolic rate.

High basal metabolic rate (BMR) is related to a powerful metabolic engine even under food shortage, which can lead to high levels of daily energy expenditure and requires more energy for maintenance in small mammals. To test the hypothesis that animals with different BMR levels respond differently to food shortage, we compared the changes in metabolism, morphology, and gene expression in response to food deprivation (FD) in male-striped hamsters (Cricetulus barabensis) with low (L)- or high (H)-BMR levels. After 36 hr of FD, energy expenditure, metabolic rate (MR), mass of body composition, and leptin and agouti-related peptide gene expressions in the white adipose tissues and the hypothalamus, respectively, decreased significantly in hamsters.

Precocious Torpor in an Altricial Mammal and the Functional Implications of Heterothermy During Development.

Most mammals and birds are altricial, small and naked at birth/hatching. They attain endothermic thermoregulation at a fraction of their adult size at a vulnerable stage with high heat loss when many could profit from using torpor for energy conservation. Nevertheless, detailed data on the interrelations between torpor expression and development of endothermic thermoregulation are currently restricted to <0.

Brown adipose tissue plays thermoregulatory role within the thermoneutral zone in Mongolian gerbils (Meriones unguiculatus).

Brown adipose tissue (BAT) plays an important role in thermoregulation and many metabolic processes in small mammals, especially in cold adaptation. However, in warm adaptation, ambient temperature cannot directly activate BAT by sympathetic nervous system. Mongolian gerbils exhibit a wider thermoneutral zone (26.

Thyroid hormones mediate metabolic rate and oxidative, anti-oxidative balance at different temperatures in Mongolian gerbils (Meriones unguiculatus).

Oxidative damage is a potential physiological cost of thermoregulation during seasonal adjustments to air temperature (T) in small mammals. Here, we hypothesized that T affects serum thyroid hormone levels and these hormones can mediate the changes in metabolic rate and oxidative damage. Mongolian gerbils (Meriones unguiculatus) were acclimated at different Ts (5 °C, 23 °C and 37 °C) for 3 weeks.

Correction to: Huddling remodels gut microbiota to reduce energy requirements in a small mammal species during cold exposure.

Following publication of the original article [1], the authors reported an error in the caption of Fig. 4.

Huddling remodels gut microbiota to reduce energy requirements in a small mammal species during cold exposure.

Background: Huddling is highly evolved as a cooperative behavioral strategy for social mammals to maximize their fitness in harsh environments. Huddling behavior can change psychological and physiological responses. The coevolution of mammals with their microbial communities confers fitness benefits to both partners.

Huddling Conserves Energy, Decreases Core Body Temperature, but Increases Activity in Brandt's Voles ().

Huddling as social thermoregulatory behavior is commonly used by small mammals to reduce heat loss and energy expenditure in the cold. Our study aimed to determine the effect of huddling behavior on energy conservation, thermogenesis, core body temperature (T) regulation and body composition in Brandt's voles (). Adult captive-bred female Brandt's voles ( = 124) (~50 g) in 31 cages with 4 individuals each were exposed to cool (23 ± 1°C) and cold (4 ± 1°C) ambient temperatures (T) and were allowed to huddle or were physically separated.

Thermal biology of two sympatric gerbil species: The physiological basis of temporal partitioning.

Sympatric species can coexist through ecological resource partitioning as for example for habitat, food or time. However, a detailed understanding of the basic thermal physiology, crucial for temporal partitioning, is currently lacking, especially for the desert rodents. Here, we compare the physiological performance with regard to thermal energetics and morphological traits of two sympatric gerbils from the Gobi desert of Inner Mongolia, China.

2-Deoxy-D-glucose, not mercaptoacetate, induces a reversible reduction of body temperature in male desert hamsters (Phodopus roborovskii).

The initiation of torpor is supposed to be related to the availability of metabolic fuels. Studies on metabolic fuel inhibition of glucose by using 2-deoxy-D-glucose (2DG) or fatty acid by mercaptoacetate (MA) in heterothermic mammals produced mixed outcomes. To examine the roles of availability of glucose and fatty acid in the initiation of torpor in desert hamsters (Phodopus roborovskii), we intraperitoneally administrated 2DG and MA to summer-acclimated male hamsters while body temperature (T), metabolic rate (MR) and respiratory quotient (RQ) were simultaneously recorded to monitor their thermoregulatory response.

The effect of aggression I: The increases of metabolic cost and mobilization of fat reserves in male striped hamsters.

Aggression can benefit individuals by enhancing their dominance and thereby their ability to acquire and retain resources that increase survival or fitness. Engaging in aggressive behavior costs energy and how animals manage their energy budget to accommodate aggression remains unclear. We conducted three experiments to examine changes in physiological, behavioral and hormonal markers indicative of energy budget in male striped hamsters subject to resident-intruder aggression tests.

The roles of metabolic thermogenesis in body fat regulation in striped hamsters fed high-fat diet at different temperatures.

The metabolic thermogenesis plays important roles in thermoregulation, and it may be also involved in body fat regulation. The thermogenesis of brown adipose tissue (BAT) is largely affected by ambient temperature, but it is unclear if the roles in body fat regulation are dependent on the temperature. In the present study, uncoupling protein 1 (ucp1)-based BAT thermogenesis, energy budget and body fat content were examined in the striped hamsters fed high fat diet (HF) at cold (5°C) and warm (30°C) temperatures.

A Central Catecholaminergic Circuit Controls Blood Glucose Levels during Stress.

Stress-induced hyperglycemia is a fundamental adaptive response that mobilizes energy stores in response to threats. Here, our examination of the contributions of the central catecholaminergic (CA) neuronal system to this adaptive response revealed that CA neurons in the ventrolateral medulla (VLM) control stress-induced hyperglycemia. Ablation of VLM CA neurons abolished the hyperglycemic response to both physical and psychological stress, whereas chemogenetic activation of these neurons was sufficient to induce hyperglycemia.

Limits to sustained energy intake XXV: milk energy output and thermogenesis in Swiss mice lactating at thermoneutrality.

Previous studies at 21 °C and 5 °C suggest that in Swiss mice sustained energy intake (SusEI) and reproductive performance are constrained by the mammary capacity to produce milk. We aimed to establish if this constraint also applied at higher ambient temperature (30 °C). Female Swiss mice lactating at 30 °C had lower asymptotic food intake and weaned lighter litters than those at 21 °C.

Fasting-induced daily torpor in desert hamsters (Phodopus roborovskii).

Daily torpor is frequently expressed in small rodents when facing energetically unfavorable ambient conditions. Desert hamsters (Phodopus roborovskii, ~20g) appear to be an exception as they have been described as homeothermic. However, we hypothesized that they can use torpor because we observed reversible decreases of body temperature (Tb) in fasted hamsters.

Effect of food restriction on energy budget in warm-acclimated striped hamsters.

The capacity of small mammals to sustain periods of food shortage largely depends on the adaptive regulation of energy budget in response to the decrease in food supply. In addition to food availability, ambient temperature (Ta) is an important factor affecting the rates of both energy intake and expenditure. To examine the effect of Ta on energy strategy and the capacity to sustain food shortage, striped hamsters were exposed to a warm condition (30°C) and were then restricted to 70% of ad libitum food intake.

Environmental metabolomics reveal geographic variation in aerobic metabolism and metabolic substrates in Mongolian gerbils (Meriones unguiculatus).

Mongolian gerbils (Meriones unguiculatus) have a large-scale distribution in northern China. Geographic physiological variations which related to energy and water metabolism are critical to animals' local adaptation and distribution. However, the underlying biochemical mechanism of such variation and its role in adaptation remains largely unknown.

Seasonal changes of body mass and energy budget in striped hamsters: the role of leptin.

Proper adjustments of physiology and behavior are required for small mammals to cope with seasonal climate change. The aim of this study was to examine the role of leptin in the regulation of body mass and energy budget in striped hamsters. We first investigated seasonal changes in body mass, energy budget, and serum leptin levels in hamsters acclimated to outdoor natural daylight and ambient temperature.

The shift of thermoneutral zone in striped hamster acclimated to different temperatures.

Temperature affects all biological functions and will therefore modulate ecologically significant interactions between animals and their environment. Here, we examined the effect of ambient temperature (Ta) on the thermal biology and energy budget in striped hamsters acclimated to cold (5°C), warm (21°C) and hot temperatures (31°C). Thermoneutral zone (TNZ) was 22.

Limits to sustained energy intake. XIX. A test of the heat dissipation limitation hypothesis in Mongolian gerbils (Meriones unguiculatus).

We evaluated factors limiting lactating Mongolian gerbils (Meriones unguiculatus) at three temperatures (10, 21 and 30°C). Energy intake and daily energy expenditure (DEE) increased with decreased ambient temperature. At peak lactation (day 14 of lactation), energy intake increased from 148.

The energy budget, thermogenic capacity and behavior in Swiss mice exposed to a consecutive decrease in temperatures.

The limitation on sustainable energy intake (SusEI) is important because it establishes the upper energetic limit on the ability of animals to disperse, survive and reproduce. However, there are still arguments about what factors impose that limitation. Thermoregulation in cold environments imposes great energy demands on small mammals.

Limits to sustainable energy budget during lactation in the striped hamster (Cricetulus barabensis) raising litters of different size.

A female animal appears to approach an upper limit to the rate of sustained energy intake/metabolic rate (SusEI/MR) during lactation. However, different species of animals may respond differently to the sustainable limit. Here, we measured energy budget during lactation in female striped hamsters raising litters of natural size (Con), and females whose litter size was manipulated during early lactation to support fewer or more pups (minus pups, MP or plus pups, PP).

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

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.