scholarly journals Continuous growth through winter correlates with increased resting metabolic rate but does not affect daily energy budgets due to torpor use

2020 ◽  
Author(s):  
Jan S Boratyński ◽  
Karolina Iwińska ◽  
Paulina A Szafrańska ◽  
Piotr Chibowski ◽  
Wiesław Bogdanowicz

Abstract Small mammals that are specialists in homeothermic thermoregulation reduce their self-maintenance costs of normothermy to survive the winter. By contrast, heterothermic ones that are considered generalists in thermoregulation can lower energy expenditure by entering torpor. It is well known that different species vary the use of their strategies to cope with harsh winters in temperate zones; however, little is still known about the intraspecific variation within populations and the associated external and internal factors. We hypothesized that yellow-necked mice Apodemus flavicollis decrease their resting metabolic rate (RMR) from autumn to winter, and then increase it during spring. However, since the alternative for seasonal reduction of RMR could be the development of heterothermy, we also considered the use of this strategy. We measured body mass (mb), RMR, and body temperature (Tb) of mice during two consecutive years. In the first year, mice decreased whole animal RMR in winter, but did not do so in the second year. All mice entered torpor during the second winter, whereas only a few did so during the first one. Mice showed a continuous increase of mb, which was steepest during the second year. The relationship between RMR and mb varied among seasons and years most likely due to different mouse development stages. The mb gain at the individual level was correlated positively with RMR and heterothermy. This indicates that high metabolism in winter supports the growth of smaller animals, which use torpor as a compensatory mechanism. Isotope composition of mice hair suggests that in the first year they fed mainly on seeds, while in the second, they likely consumed significant amounts of less digestible herbs. The study suggests that the use of specialist or generalist thermoregulatory strategies can differ with environmental variation and associated differences in developmental processes.

Author(s):  
William A. Buttemer ◽  
Vincent Careau ◽  
Mark A. Chappell ◽  
Simon C. Griffith

Evidence from a number of species suggests behaviours associated with social rank are positively correlated with metabolic rate. These studies, however, are based on metabolic measurements of isolated individuals, thereby ignoring potential effects of social interactions on metabolic rates. Here, we characterised three pertinent metabolic indices in the two predominant genetic colour morphs of the Gouldian finch (Erythrura gouldiae): diurnal resting metabolic rate (RMR), nocturnal basal metabolic rate (BMR), and exercise-induced maximal metabolic rate (MMR). Research reveals red-headed morphs consistently dominate the less aggressive black-headed morphs and the two morphs to differ in other behavioural and physiological traits. We measured daytime RMR of intermorph naïve birds (first-year virgin males maintained in total isolation from opposite colour morphs) and their metabolic responses to viewing a socially unfamiliar bird of each colour. Subsequently each bird was placed in a home cage with an opposite colour morph (intermorph exposed) and the series of measurements repeated. Daytime RMR was indistinguishable between the two morphs, whether intermorph naïve or intermorph exposed. However, both red- and black-headed birds showed a greater short-term increase in metabolic rate when viewing an unfamiliar red-headed bird than when seeing a black-headed bird, but only when intermorph naïve. Measurements of BMR and exercise-induced MMR did not differ between the two morphs, and consequently aerobic scope was indistinguishable between them. We propose that the suite of behavioural differences between these two sympatric morphs are functionally complementary and represent evolutionary stable strategies permitting establishment of dominance status in the absence of metabolic costs.


2011 ◽  
Vol 89 (11) ◽  
pp. 1146-1155 ◽  
Author(s):  
Nicholas Robar ◽  
Dennis L. Murray ◽  
Gary Burness

Detrimental effects of parasitism on host fitness are frequently attributed to parasite-associated perturbations to host energy budgets. It has therefore been widely hypothesized that energetic costs of infection may be manifest as changes in host resting metabolic rate (RMR). Attempts to quantify these effects have yielded contradictory results across host–parasite systems. We used a meta-analysis of the literature to test the effects of parasites on mass-specific (n = 22) and whole-body (n = 15) host RMR. Parasites resulted in a qualitative increase in host RMR in the majority of studies; however, the overall effect of parasites on host RMR was small and statistically nonsignificant. Additionally, substantial among-study variation in host RMR could not be explained by any of the tested covariates. We conclude that the lack of an overall effect of parasites on host metabolism reflects inconsistent directionality and varying magnitudes of parasite-associated effects across studies, rather than an absence of system-specific effects. We contend that a general understanding of parasite effects on host energetics may be best achieved through identifying mechanisms underlying among-system variance in parasite effects on host RMR and relating parasite-associated perturbations of host energy budgets to robust estimates of host fitness.


2006 ◽  
Vol 25 (2) ◽  
pp. 123-127 ◽  
Author(s):  
Laleh Hajhosseini ◽  
Tawni Holmes ◽  
Parinez Mohamadi ◽  
Vida Goudarzi ◽  
Lucy McProud ◽  
...  

2020 ◽  
Vol 223 (17) ◽  
pp. jeb231415
Author(s):  
Guang-Min Deng ◽  
Jing-Xin Yu ◽  
Jia-Qi Xu ◽  
Yu-Fan Bao ◽  
Qian Chen ◽  
...  

ABSTRACTHigh temperatures and heatwaves are rapidly emerging as an important threat to many aspects of physiology and behavior in females during lactation. The body's capacity to dissipate heat is reduced by high ambient temperatures, increasing the risk of hyperthermia. Exposure to wind, a pervasive environmental factor for most terrestrial animals, is known to increase heat loss, but its effects on the reproductive performance of small mammals remains unclear. In the present study, the effects of wind on the energy budgets, resting metabolic rate and milk energy output (MEO) were measured in lactating Swiss mice at 21 and 32.5°C. Females kept at 32.5°C had a significantly lower resting metabolic rate, food intake and MEO, and lighter offspring, than those kept at 21°C. However, exposure to wind increased the asymptotic food intake of females kept at 32.5°C by 22.5% (P<0.01), their MEO by 20.7% (P<0.05) and their litter mass by 17.6% (P<0.05). The body temperature of females kept at 32.5°C was significantly higher during lactation than that of females kept at 21°C, but this difference was reduced by exposure to wind. These findings suggest that exposure to wind considerably improves reproductive performance, increasing the fitness of small mammals while undergoing hot temperatures during heatwaves.


1997 ◽  
Vol 75 (5) ◽  
pp. 731-739 ◽  
Author(s):  
Christiane Mauget ◽  
Robert Mauget ◽  
Antoine Sempéré

Indirect calorimetry measurements were made continuously over a 2-year period in 10 adult female roe deer (Capreolus capreolus) maintained in outdoor enclosures on ad libitum feeding. Results from adult nonpregnant does revealed no endogenous seasonal rhythm in resting metabolic rate (RMR), in contrast to most cervid species. Throughout the 2 years of our study, RMR (overall mean 4695 ± 65 kJ∙d−1) fluctuated in parallel with variations in body mass. The mass-specific RMR ranged from 221.2 ± 4.8 to 230.7 ± 4.0 kJ∙kg−1∙d−1 (466.0 ± 10.8 to 495.5 ± 9.7 kJ∙kg−0.75∙d−1). Results from pregnant females (five in the first year, four in the second) showed that their energy expenditure increased by 15% during the last 2 months of gestation, in step with the increase in body mass. A 27% increase in RMR was recorded in lactating females during the first month post partum. These results show that in a small-bodied cervid such as the roe deer, reproduction costs are no higher than in other wild herbivores.


Author(s):  
Habib Yarizadeh ◽  
Leila Setayesh ◽  
Caroline Roberts ◽  
Mir Saeed Yekaninejad ◽  
Khadijeh Mirzaei

Abstract. Objectives: Obesity plays an important role in the development of chronic diseases including cardiovascular disease and diabetes. A low resting metabolic rate (RMR) for a given body size and composition is a risk factor for obesity, however, there is limited evidence available regarding the association of nutrient patterns and RMR. The aim of this study was to determine the association of nutrient patterns and RMR in overweight and obese women. Study design: This cross-sectional study was conducted on 360 women who were overweight or obese. Method: Dietary intake was assessed using a semi-quantitative standard food frequency questionnaire (FFQ). Nutrient patterns were also extracted by principal components analysis (PCA). All participants were evaluated for their body composition, RMR, and blood parameters. Result: Three nutrient patterns explaining 64% of the variance in dietary nutrients consumption were identified as B-complex-mineral, antioxidant, and unsaturated fatty acid and vitamin E (USFA-vit E) respectively. Participants were categorized into two groups based on the nutrient patterns. High scores of USFA-vit E pattern was significantly associated with the increase of RMR (β = 0.13, 95% CI = 0.79 to 68.16, p = 0.04). No significant associations were found among B-complex-mineral pattern (β = −0.00, 95% CI = −49.67 to 46.03, p = 0.94) and antioxidant pattern (β = 0.03, 95% CI −41.42 to 22.59, p = 0.56) with RMR. Conclusion: Our results suggested that the “USFA-vit E” pattern (such as PUFA, oleic, linoleic, vit.E, α-tocopherol and EPA) was associated with increased RMR.


2020 ◽  
Vol 5 (1) ◽  
pp. 74-89
Author(s):  
Hugh Crago

In a seminal 1973 paper, Robert Clark described the very different “cultures” of the first and second year students in a four year clinical psychology PhD programme. The author applies Clark’s template to his own experiences as trainee or trainer in five different counsellor education programmes, one in the US and four in Australia. Each of the programmes, to varying degrees, demonstrates key features of the pattern identified by Clark, where the first year is “therapeutic” and other-oriented, the second is “professional” and self-focused. The author concludes that all the surveyed programmes exhibited some level of “second year crisis”, in which a significant number of students felt abandoned, dissatisfied, or rebellious. The author extends and refines Clark’s developmental analogy (first year = childhood; second year = adolescence) to reflect recent neurological research, in particular, the shift from a right hemisphere-dominant first year of life, prioritising affiliative needs, to a left hemisphere-dominant second year, prioritising autonomy and control. This shift is paralleled later by a more gradual move from a protective, supportive childhood to necessary, but sometimes conflictual, individuation in adolescence. The first two years of a counsellor training programme broadly echo this process, a process exacerbated by the second year internship/placement, in which students must “leave home” and adjust to unfamiliar, potentially less nurturing, authority figures. Finally, the author suggests introducing more rigorous “academic holding” into the first year, and greater attention to “therapeutic holding” of dissident students in the second, hopefully decreasing student dropout, and achieving a better balanced training experience.


Author(s):  
Umar Iqbal ◽  
Deena Salem ◽  
David Strong

The objective of this paper is to document the experience of developing and implementing a second-year course in an engineering professional spine that was developed in a first-tier research university and relies on project-based core courses. The main objective of this spine is to develop the students’ cognitive and employability skills that will allow them to stand out from the crowd of other engineering graduates.The spine was developed and delivered for the first time in the academic year 2010-2011 for first-year general engineering students. In the year 2011-2012, those students joined different programs, and accordingly the second-year course was tailored to align with the different programs’ learning outcomes. This paper discusses the development and implementation of the course in the Electrical and Computer Engineering (ECE) department.


Author(s):  
Pathima Fairoosa ◽  
Indu Waidyatilaka ◽  
Maduka de Lanerolle-Dias ◽  
Pujitha Wickramasinghe ◽  
Pulani Lanerolle

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