Seasonal trends in body mass, food intake and resting metabolic rate, and induction of metabolic depression in arctic foxes ( Alopex lagopus ) at Svalbard

1999 ◽  
Vol 169 (6) ◽  
pp. 361-369 ◽  
Author(s):  
E. Fuglei ◽  
N. A. Øritsland
2009 ◽  
Vol 55 (4) ◽  
pp. 249-257 ◽  
Author(s):  
Zhijun Zhao ◽  
Jing Cao ◽  
Ye Tian ◽  
Ruirui Wang ◽  
Guiying Wang

Abstract When small animals are faced with an unpredictable food supply, they can adapt by altering different components of their energy budget such as energy intake, metabolic rate, rate of non-shivering thermogenesis (NST) or behaviour. The present study examined the effect of stochastic food deprivation (FD) on body mass, food intake, resting metabolic rate (RMR), NST and behaviour in male Swiss mice. During a period of 4 weeks’ FD, animals were fed ad libitum for a randomly assigned 4 days each week, but were deprived of food for the other 3 days. The results showed that body mass significantly dropped on FD days compared to controls. Food intake of FD mice increased significantly on ad libitum days, ensuring cumulative food intake, final body mass, fat mass, RMR and NST did not differ significantly from controls. Moreover, gastrointestinal tract mass increased in FD mice, but digestibility decreased. In general, activity was higher on deprived days, and feeding behaviour was higher on ad libitum days suggesting that Swiss mice are able to compensate for stochastic FD primarily by increasing food intake on ad libitum days, and not by reducing energy expenditure related to RMR or NST.


2001 ◽  
Vol 204 (4) ◽  
pp. 777-784 ◽  
Author(s):  
C. Selman ◽  
S. Lumsden ◽  
L. Bunger ◽  
W.G. Hill ◽  
J.R. Speakman

We investigated the relationship between resting metabolic rate (RMR) and various morphological parameters in non-breeding mice, selected for high and low food intake corrected for body mass. RMR was measured at 30 degrees C, and mice were subsequently killed and dissected into 19 body components. High-food-intake mice had significantly greater body masses and a significantly elevated RMR compared with the low-intake mice. Data pooled across strains indicated that body mass, sex and strain together explained over 56 % of the observed variation in RMR. The effects of strain and sex on RMR and tissue morphology were removed, and three separate statistical analyses to investigate the relationship between RMR and organ morphology were performed: (i) employing individual regression analysis with each tissue component as a separate predictor against RMR; (ii) individual regression analysis with residual organ mass against residual RMR (i.e. with strain, sex and body mass effects removed); and (iii) pooling of some organ masses into functional groupings to reduce the number of predictors. Liver mass was the most significant morphological trait linked to differences in RMR. Small intestine length was significantly greater in the high-intake line; however, no difference was observed between strains in the dry mass of this organ, and there was no evidence to associate variability in the mass of the alimentary tract with variability in RMR. The effects of strain on RMR independent of the effect on body mass were consistent with the anticipated effect from the strain differences in the size of the liver.


2020 ◽  
Vol 70 (2) ◽  
pp. 175-187
Author(s):  
Peng Hong-bi ◽  
Hou Dong-min ◽  
Zhang Di ◽  
Zhu Wan-long

Abstract The metabolic switch hypothesis refers to an ability to adjust metabolic rate. It plays a key role in animals adapted to periods of food shortage, enabling them to “switch down” their resting metabolic rate and to survive and maintain their weight indefinitely on limited rations. The present study investigates the energy strategies of a small mammal in response to food shortages as a function of food restriction, metabolic rate and ambient temperature. We subjected tree shrews (Tupaia belangeri) to food restriction and measured body mass, survival rate, resting metabolic rate, non-shivering thermogenesis and cytochrome c oxidase activity of brown adipose tissue. Cold-exposed animals restricted to 80% of ad libitum food intake had significantly increased resting metabolic rate and non-shivering thermogenesis and decreased body mass and survival rates compared with those kept as control group on the same ood restriction level. Animals classified as having a high resting metabolic rate consumed 30.69% more food than those classified as having a low resting metabolic rate, but showed no differences in body mass or survival when restricted to 80% of ad libitum food intake. These results indicate that tree shrews, known for their relatively high metabolic rates, are sensitive to periods of food restriction, which supports the metabolic switch hypothesis. Our findings are also consistent with the prediction that small mammals with food hoarding behaviors, like tree shrews, may have a lower tolerance for food shortages than non-hoarding species.


2020 ◽  
Vol 223 (21) ◽  
pp. jeb231993
Author(s):  
Kimberley J. Mathot ◽  
Eva M. A. Kok ◽  
Piet van den Hout ◽  
Anne Dekinga ◽  
Theunis Piersma

ABSTRACTMass regulation in birds is well documented. For example, birds can increase body mass in response to lower availability and/or predictability of food and decrease body mass in response to increased predation danger. Birds also demonstrate an ability to maintain body mass across a range of food qualities. Although the adaptive significance of mass regulation has received a great deal of theoretical and empirical attention, the mechanisms by which birds achieve this have not. Several non-exclusive mechanisms could facilitate mass regulation in birds. Birds could regulate body mass by adjusting food intake (dieting), activity, baseline energetic requirements (basal metabolic rate), mitochondrial efficiency or assimilation efficiency. Here, we present the results of two experiments in captive red knots (Calidris canutus islandica) that assess three of these proposed mechanisms: dieting, activity and up- and down-regulation of metabolic rate. In the first experiment, knots were exposed to cues of predation risk that led them to exhibit presumably adaptive mass loss. In the second experiment, knots maintained constant body mass despite being fed alternating high- and low-quality diets. In both experiments, regulation of body mass was achieved through a combination of changes in food intake and activity. Both experiments also provide some evidence for a role of metabolic adjustments. Taken together, these two experiments demonstrate that fine-scale management of body mass in knots is achieved through multiple mechanisms acting simultaneously.


2010 ◽  
Vol 57 (3-4) ◽  
pp. 221-227 ◽  
Author(s):  
Katarina Melzer ◽  
Yves Schutz ◽  
Nina Soehnchen ◽  
Veronique Othenin Girard ◽  
Begona Martinez de Tejada ◽  
...  

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