scholarly journals The metabolic response of the Bradypus sloth to temperature

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5600 ◽  
Author(s):  
Rebecca Naomi Cliffe ◽  
David Michael Scantlebury ◽  
Sarah Jane Kennedy ◽  
Judy Avey-Arroyo ◽  
Daniel Mindich ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Body Temperature ◽  
Energy Expenditure ◽  
High Power ◽  
Metabolic Response ◽  
Metabolic Responses ◽  
Metabolic Depression ◽  
Wide Range ◽  
Energetic Constraints ◽  
Power Costs

Poikilotherms and homeotherms have different, well-defined metabolic responses to ambient temperature (Ta), but both groups have high power costs at high temperatures. Sloths (Bradypus) are critically limited by rates of energy acquisition and it has previously been suggested that their unusual departure from homeothermy mitigates the associated costs. No studies, however, have examined how sloth body temperature and metabolic rate vary with Ta. Here we measured the oxygen consumption (VO2) of eight brown-throated sloths (B. variegatus) at variable Ta’s and found that VO2 indeed varied in an unusual manner with what appeared to be a reversal of the standard homeotherm pattern. Sloth VO2 increased with Ta, peaking in a metabolic plateau (nominal ‘thermally-active zone’ (TAZ)) before decreasing again at higher Ta values. We suggest that this pattern enables sloths to minimise energy expenditure over a wide range of conditions, which is likely to be crucial for survival in an animal that operates under severe energetic constraints. To our knowledge, this is the first evidence of a mammal provisionally invoking metabolic depression in response to increasing Ta’s, without entering into a state of torpor, aestivation or hibernation.

Physiological and Metabolic Responses to Exercise on Treadmill, Elliptical Trainer, and Stepper: Practical Implications for Training

2020 ◽  
pp. 1-8
Author(s):  
Andrew N. Bosch ◽  
Kirsten C. Flanagan ◽  
Maaike M. Eken ◽  
Adrian Withers ◽  
Jana Burger ◽  
...  
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Energy Expenditure ◽  
Physiological Responses ◽  
Maximal Oxygen Consumption ◽  
Metabolic Responses ◽  
Physiological Measures ◽  
Fuel Utilization ◽  
Trained Runners ◽  
Practical Implications

Elliptical trainers and steppers are proposed as useful exercise modalities in the rehabilitation of injured runners due to the reduced stress on muscles and joints when compared to running. This study compared the physiological responses to submaximal running (treadmill) with exercise on the elliptical trainer and stepper devices at three submaximal but identical workloads. Authors had 18 trained runners (male/female: N = 9/9, age: mean ± SD = 23 ± 3 years) complete randomized maximal oxygen consumption tests on all three modalities. Submaximal tests of 3 min were performed at 60%, 70%, and 80% of peak workload individually established for each modality. Breath-by-breath oxygen consumption, heart rate, fuel utilization, and energy expenditure were determined. The value of maximal oxygen consumption was not different between treadmill, elliptical, and stepper (49.3 ± 5.3, 48.0 ± 6.6, and 46.7 ± 6.2 ml·min−1·kg−1, respectively). Both physiological measures (oxygen consumption and heart rate) as well as carbohydrate and fat oxidation differed significantly between the different exercise intensities (60%, 70%, and 80%) but did not differ between the treadmill, elliptical trainer, and stepper. Therefore, the elliptical trainer and stepper are suitable substitutes for running during periods when a reduced running load is required, such as during rehabilitation from running-induced injury.

Ventilatory and metabolic responses to hypoxia in the smallest simian primate, the pygmy marmoset

2002 ◽  
Vol 92 (1) ◽  
pp. 202-210 ◽  
Author(s):  
Glenn J. Tattersall ◽  
James L. Blank ◽  
Stephen C. Wood
Keyword(s):  
Body Temperature ◽  
Metabolic Response ◽  
World Monkey ◽  
Minute Ventilation ◽  
Metabolic Depression ◽  
Hypoxic Conditions ◽  
Pygmy Marmoset ◽  
Average Body Mass ◽  
Average Body ◽  
Ventilatory Response To Hypoxia

The pygmy marmoset ( Cebuella pygmaea) is the smallest New World Monkey (average body mass of 120–130 g). As such, it faces possible challenges to thermoregulation. Small mammals (e.g., rats) are well known to lower body temperature and metabolism in response to hypoxia; however, small primates have not been studied in this respect nor have, in general, the interactions between metabolism and ventilation. Because little is known about these responses in small primates, it seemed of great interest to assess the hypoxia-induced metabolic depression and drop in body temperature and the associated ventilatory requirements in this species under hypoxic conditions. Exposure to graded hypoxia (30 min at each of 18, 16, 14, 12, and 10% O2) caused body temperature to drop from the normoxic value of 39 to 37°C. This was accompanied by a marked metabolic depression (O2 consumption was ∼68% of the normoxic value, implying a suppression of metabolism greater than that predicted from a typical value of the effect of 10°C change on metabolism of 2–3 times). Minute ventilation declined in parallel to metabolism, maintaining a constant air-convection requirement during hypoxia; thus this species did not show the typical mammalian hyperventilation. Acute exposure to 10% O2 led to a similar overall decline in metabolism and body temperature and qualitative differences in the timing of these changes. The pygmy marmoset shares some similarities in its hypoxic metabolic response with other mammals of similar size yet appears to be unique in its much diminished ventilatory response to hypoxia.

Heat exchanges in wet suits

1985 ◽  
Vol 58 (3) ◽  
pp. 770-777 ◽  
Author(s):  
A. H. Wolff ◽  
S. R. Coleshaw ◽  
C. G. Newstead ◽  
W. R. Keatinge
Keyword(s):  
Body Temperature ◽  
Water Temperature ◽  
Cold Water ◽  
Whole Body ◽  
Metabolic Responses ◽  
Body Temperatures ◽  
Postural Changes ◽  
Wide Range ◽  
Heat Exchanges ◽  
Skin Temperatures

Flow of water under foam neoprene wet suits could halve insulation that the suits provided, even at rest in cold water. On the trunk conductance of this flow was approximately 6.6 at rest and 11.4 W . m-2 . C-1 exercising; on the limbs, it was only 3.4 at rest and 5.8 W . m-2 . degrees C-1 exercising; but during vasoconstriction in the cold, skin temperatures on distal parts of limbs were lower than were those of the trunk, allowing adequate metabolic responses. In warm water, minor postural changes and movement made flow under suits much higher, approximately 60 on trunk and 30 W . m-2 . degrees C-1 on limbs, both at rest and at work. These changes in flow allowed for a wide range of water temperatures at which people could stabilize body temperature in any given suit, neither overheating when exercising nor cooling below 35 degrees C when still. Even thin people with 4- or 7- mm suits covering the whole body could stabilize their body temperatures in water near 10 degrees C in spite of cold vasodilatation. Equations to predict limits of water temperature for stability with various suits and fat thicknesses are given.

Defending body mass during food restriction in Acomys russatus: a desert rodent that does not store food

2006 ◽  
Vol 290 (4) ◽  
pp. R881-R891 ◽  
Author(s):  
Roee Gutman ◽  
Itzhak Choshniak ◽  
Noga Kronfeld-Schor
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Body Temperature ◽  
Energy Expenditure ◽  
Body Mass ◽  
Food Restriction ◽  
Daily Torpor ◽  
Spiny Mice ◽  
Desert Rodent ◽  
Initial Decrease

Golden spiny mice, which inhabit rocky deserts and do not store food, must therefore employ physiological means to cope with periods of food shortage. Here we studied the physiological means used by golden spiny mice for conserving energy during food restriction and refeeding and the mechanism by which food consumption may influence thermoregulatory mechanisms and metabolic rate. As comparison, we studied the response to food restriction of another rocky desert rodent, Wagner’s gerbil, which accumulates large seed caches. Ten out of 12 food-restricted spiny mice (resistant) were able to defend their body mass after an initial decrease, as opposed to Wagner’s gerbils ( n = 6). Two of the spiny mice (nonresistant) kept losing weight, and their food restriction was halted. In four resistant and two nonresistant spiny mice, we measured heart rate, body temperature, and oxygen consumption during food restriction. The resistant spiny mice significantly ( P < 0.05) reduced energy expenditure and entered daily torpor. The nonresistant spiny mice did not reduce their energy expenditure. The gerbils’ response to food restriction was similar to that of the nonresistant spiny mice. Resistant spiny mice leptin levels dropped significantly ( n = 6, P < 0.05) after 24 h of food restriction, and continued to decrease throughout food restriction, as did body fat. During refeeding, although the golden spiny mice gained fat, leptin levels were not correlated with body mass ( r2 = 0.014). It is possible that this low correlation allows them to continue eating and accumulate fat when food is plentiful.

Activity and energy expenditure in laying hens

1976 ◽  
Vol 86 (3) ◽  
pp. 471-473 ◽  
Author(s):  
M. Van Kampen
Keyword(s):  
Oxygen Consumption ◽  
Locomotor Activity ◽  
Body Temperature ◽  
Energy Expenditure ◽  
Oxygen Uptake ◽  
Heat Production ◽  
Energy Cost ◽  
Laying Hens ◽  
Different Types ◽  
Nesting Activity

SummaryThe energy cost of nesting activity and oviposition of hens in different environments has been determined.The oxygen consumption of hens on a wire floor reached a peak during the last 15 min before oviposition. However, the oxygen uptake of hens accustomed to a litter floor had fallen to a minimum at this time.The energy cost of expelling the egg is minimal. There is a good correlation between the locomotor activity and the heat production.The variations in heat production and body temperature on different types of floors are explicable by the differences in nesting activity.

scholarly journals Metabolic Responses of Two Contrasting Lentil Genotypes to PEG-Induced Drought Stress

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1190
Author(s):  
Chrysanthi Foti ◽  
Ioannis F. Kalampokis ◽  
Konstantinos A. Aliferis ◽  
Ourania I. Pavli
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Metabolic Response ◽  
Early Growth ◽  
Metabolic Responses ◽  
Economic Losses ◽  
Growth Stages ◽  
Wide Range ◽  
Research Findings ◽  
Post Transcriptional Regulation

Among abiotic stresses, drought is undoubtedly one of the most severe environmental factors for a wide range of major crops, leading to considerable yield and economic losses. The adverse effects in crop yield reflect the result of a series of morphological and physiological changes but also changes in signaling pathways, transcriptional and post-transcriptional regulation of stress-responsive genes, and metabolic adaptations. Despite the exhausting studies elucidating plants’ metabolic response to drought, there is a knowledge gap in the biochemical mechanisms governing drought tolerance in lentil (Lens culinaris Medik.). The present study aimed to determine the fluctuations of the metabolite profiles of lentil genotypes with contrasting drought tolerance to discover possible biomarkers for screening tolerant genotypes at early growth stages. Lentil seedlings were subjected to osmotic drought stress, induced by polyethylene glycol, at two stress levels (2.5% and 5.0% PEG-6000) for a period of 20 days, while untreated plants were also included as controls. GC/ΕΙ/MS-mediated metabolic profiling was employed to monitor changes in response to osmotic drought stress. The data was subjected to OPLS-DA and OPLS-HCA for the discrimination between treatments and the discovery of trends and corresponding biomarkers. In total, the analysis yielded 150 metabolite features with highly reproducible patterns, of which the vast majority belonged to carbohydrates, carboxylic acids, and amino acids. Overall, findings highlight the differential accumulation of a series of compounds, and more importantly, the variable accumulation of certain metabolites, namely D-fructose, α,α-trehalose, myo-inositol, and L-tryptophan, in the contrasting genotypes, indicating that the adaptive metabolic responses to osmotic drought stress operate under strong genotypic dependency in lentil. Research findings provide insights into various aspects of lentil’s metabolism under drought and further offer the possibility of applying such knowledge towards effectively screening for drought-tolerant lentil germplasm at early growth stages.

scholarly journals Energy expenditure for isometric contractions of right and left ventricular trabeculae over a wide range of frequencies at body temperature

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Toan Pham ◽  
Callum M. Zgierski-Johnston ◽  
Kenneth Tran ◽  
Andrew J. Taberner ◽  
Denis S. Loiselle ◽  
...  
Keyword(s):  
Body Temperature ◽  
Energy Expenditure ◽  
Left Ventricular ◽  
Isometric Contractions ◽  
Wide Range ◽  
Ventricular Trabeculae

Respiratory metabolism studies on red-winged blackbird nestlings

1968 ◽  
Vol 46 (2) ◽  
pp. 223-233 ◽  
Author(s):  
M. I. Dyer
Keyword(s):  
Oxygen Consumption ◽  
Body Temperature ◽  
Temperature Gradient ◽  
Respiratory Quotient ◽  
Environmental Temperature ◽  
Metabolic Response ◽  
Respiratory Metabolism ◽  
Nestling Period ◽  
Metabolic Reactions ◽  
Two Populations

Nestling red-winged blackbirds exhibited two distinct metabolic reactions to lowering temperatures. One group, which maintained homeothermic conditions, elevated its metabolism linearly according to a drop in ambient temperature and the second decreased its metabolic response in a curvilinear fashion. Core temperatures showed that although there was a progression toward the establishment of homeothermy throughout the nestling period, the birds could and did drop their core temperatures when the temperature gradient was too great to maintain constant body temperature. In some instances it is felt that oxygen consumption, and thus metabolism, was lowered before body temperature was suddenly dropped. No differences in the rates of metabolism could be found between upland and marshland populations; however, differences between values of the respiratory quotient for the two populations were found (p < 0.001). In addition differences in R.Q. values were found between well-developed nestlings practicing homeothermy and those that became hypothermic in response to lowering environmental temperature.

scholarly journals Calculating metabolic energy expenditure across a wide range of exercise intensities: the equation matters

2018 ◽  
Vol 43 (6) ◽  
pp. 639-642 ◽  
Author(s):  
Shalaya Kipp ◽  
William C. Byrnes ◽  
Rodger Kram
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Energy Expenditure ◽  
Metabolic Rate ◽  
Carbon Dioxide Production ◽  
Metabolic Energy ◽  
Distance Runners ◽  
Wide Range ◽  
Using Data ◽  
Metabolic Energy Expenditure

We compared 10 published equations for calculating energy expenditure from oxygen consumption and carbon dioxide production using data for 10 high-caliber male distance runners over a wide range of running velocities. We found up to a 5.2% difference in calculated metabolic rate between 2 widely used equations. We urge our fellow researchers abandon out-of-date equations with published acknowledgments of errors or inappropriate biochemical/physical assumptions.

Polar bear locomotion: body temperature and energetic cost

1982 ◽  
Vol 60 (1) ◽  
pp. 40-44 ◽  
Author(s):  
R. J. Hurst ◽  
M. L. Leonard ◽  
P. D. Watts ◽  
P. Beckerton ◽  
N. A. Øritsland
Keyword(s):  
Oxygen Consumption ◽  
Body Temperature ◽  
Polar Bear ◽  
Metabolic Response ◽  
Energetic Cost ◽  
Deep Body Temperature ◽  
Hunting Strategies ◽  
Relative Inability ◽  
Walking Speeds ◽  
Deep Body

The metabolic response of a 190-kg polar bear was tested at four different walking speeds within a respiration chamber mounted on a treadmill. Regressions of deep body temperature and oxygen consumption as a function of walking speed were determined. Equilibrium deep body temperature increased exponentially with speed of locomotion and indicated a relative inability to dissipate metabolic heat at high walking speeds. Metabolic rate, as measured by weight-specific oxygen consumption, was also best fit by a curvilinear equation and was twice that predicted by a general equation for quadruped locomotion. The apparent inefficiency of locomotion in polar bears suggests a compromise between thermoregulation, hunting strategies, and economy of transport.

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