Effects of parasites on host energy expenditure: the resting metabolic rate stalemate

2011 ◽  
Vol 89 (11) ◽  
pp. 1146-1155 ◽  
Author(s):  
Nicholas Robar ◽  
Dennis L. Murray ◽  
Gary Burness
Keyword(s):  
Metabolic Rate ◽  
Meta Analysis ◽  
Resting Metabolic Rate ◽  
Whole Body ◽  
Energy Budgets ◽  
Host Fitness ◽  
Robust Estimates ◽  
Specific Effects ◽  
Host Parasite ◽  
Host Metabolism

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.

scholarly journals Meta-analysis of resting metabolic rate in formerly obese subjects

1999 ◽  
Vol 69 (6) ◽  
pp. 1117-1122 ◽  
Author(s):  
Arne Astrup ◽  
Peter C Gøtzsche ◽  
Karen van de Werken ◽  
Claudia Ranneries ◽  
Søren Toubro ◽  
...  
Keyword(s):  
Metabolic Rate ◽  
Meta Analysis ◽  
Resting Metabolic Rate ◽  
Obese Subjects

scholarly journals Blood flow to long bones indicates activity metabolism in mammals, reptiles and dinosaurs

2011 ◽  
Vol 279 (1728) ◽  
pp. 451-456 ◽  
Author(s):  
Roger S. Seymour ◽  
Sarah L. Smith ◽  
Craig R. White ◽  
Donald M. Henderson ◽  
Daniela Schwarz-Wings
Keyword(s):  
Blood Flow ◽  
Body Size ◽  
Metabolic Rate ◽  
Bone Cells ◽  
Bone Remodelling ◽  
Resting Metabolic Rate ◽  
Blood Flow Rate ◽  
Whole Body ◽  
Long Bone ◽  
Cross Sectional

The cross-sectional area of a nutrient foramen of a long bone is related to blood flow requirements of the internal bone cells that are essential for dynamic bone remodelling. Foramen area increases with body size in parallel among living mammals and non-varanid reptiles, but is significantly larger in mammals. An index of blood flow rate through the foramina is about 10 times higher in mammals than in reptiles, and even higher if differences in blood pressure are considered. The scaling of foramen size correlates well with maximum whole-body metabolic rate during exercise in mammals and reptiles, but less well with resting metabolic rate. This relates to the role of blood flow associated with bone remodelling during and following activity. Mammals and varanid lizards have much higher aerobic metabolic rates and exercise-induced bone remodelling than non-varanid reptiles. Foramen areas of 10 species of dinosaur from five taxonomic groups are generally larger than from mammals, indicating a routinely highly active and aerobic lifestyle. The simple measurement holds possibilities offers the possibility of assessing other groups of extinct and living vertebrates in relation to body size, behaviour and habitat.

Relationship of resting metabolic rate to body composition and protein turnover

1990 ◽  
Vol 258 (6) ◽  
pp. E990-E998 ◽  
Author(s):  
S. Welle ◽  
K. S. Nair
Keyword(s):  
Protein Synthesis ◽  
Metabolic Rate ◽  
Protein Turnover ◽  
Resting Metabolic Rate ◽  
Whole Body ◽  
Simultaneous Estimation ◽  
Total Body Potassium ◽  
Average Value ◽  
Total Body ◽  
Relationship Of

This study examined whether variability among healthy young adults in resting metabolic rate, normalized for the amount of metabolically active tissue (assessed by total body potassium), is related to protein turnover. Resting metabolic rate was measured by indirect calorimetry for 2 h in 26 men and 21 women, 19-33 yr old, with simultaneous estimation of protein turnover during a 4-h infusion of L-[1-13C]leucine. After adjusting metabolic rate for total body potassium, the standard deviation was only 89 kcal/day, or 5.5% of the average value. There was a high correlation between leucine flux (an index of proteolysis) and metabolic rate (r = 0.84) and between the nonoxidized portion of leucine flux (an index of protein synthesis) and metabolic rate (r = 0.83). This relationship was weaker, but still significant, after adjusting leucine metabolism and metabolic rate for total body potassium (r = 0.36 for leucine flux vs. metabolic rate, r = 0.33 for nonoxidized portion of leucine flux vs. metabolic rate, P less than 0.05). The regression analysis suggested that the contribution of protein turnover to resting metabolic rate was approximately 20% in an average subject. Metabolic rate and protein turnover were highest in the subjects with the greatest amount of body fat, even after accounting for differences in whole body potassium. Neither resting metabolic rate nor protein turnover was related to total or free concentrations of thyroxine or triiodothyronine, within the euthyroid range.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Association Between Cardiac High-Energy Phosphate Metabolism and Whole Body Metabolism in Healthy Female Adults

2021 ◽  
pp. 393-399
Author(s):  
P WIBOWO ◽  
S CHARMAN ◽  
N OKWOSE ◽  
L VELICKI ◽  
D POPOVIC ◽  
...  
Keyword(s):  
Metabolic Rate ◽  
Resting Metabolic Rate ◽  
High Energy ◽  
Whole Body ◽  
Phosphate Metabolism ◽  
High Energy Phosphate ◽  
Glucose Levels ◽  
Whole Body Metabolism ◽  
High Energy Phosphate Metabolism ◽  
The Relationship

Decline in cardiac high-energy phosphate metabolism [phosphocreatine-to-ATP (PCr/ATP) ratio] and whole body metabolism increase the risk of heart failure and metabolic diseases. The aim of the present study was to assess the relationship between PCr/ATP ratio and measures of body metabolic function. A total of 35 healthy women (56±14.0 years of age) underwent cardiac 31P magnetic resonance spectroscopy to assess PCr/ATP ratio – an index of cardiac high-energy phosphate metabolism. Fasting and 2-hour glucose levels were assessed using oral glucose tolerance test. Indirect calorimetry was performed to determine oxygen consumption and resting metabolic rate. There were no significant relationships between PCr/ATP ratio and resting metabolic rate (r=-0.09, p=0.62), oxygen consumption (r=-0.11, p=0.54), fasting glucose levels (r=-0.31, p=0.07), and 2-hour plasma glucose (r=-0.10, p=0.58). Adjusted analysis for covariates including age, body mass index, fat mass, and physical activity, had no significant influence on the relationship between PCr/ATP ratio and body metabolism. In conclusion, the lack of relationship between cardiac PCr/ATP ratio, glucose control and metabolic rate may suggest that overall metabolic function does not influence cardiac high-energy phosphate metabolism.

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
Keyword(s):  
Metabolic Rate ◽  
Isotope Composition ◽  
Resting Metabolic Rate ◽  
Energy Budgets ◽  
First Year ◽  
Compensatory Mechanism ◽  
Mouse Development ◽  
Continuous Increase ◽  
Continuous Growth ◽  
Second Year

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.

The ontogeny of metabolic rate and thermoregulatory capabilities of northern fur seal, Callorhinus ursinus, pups in air and water

2000 ◽  
Vol 203 (6) ◽  
pp. 1003-1016 ◽  
Author(s):  
M.J. Donohue ◽  
D.P. Costa ◽  
M.E. Goebel ◽  
J.D. Baker
Keyword(s):  
Metabolic Rate ◽  
Developmental Stages ◽  
Resting Metabolic Rate ◽  
Thermal Conductance ◽  
Open Circuit ◽  
Whole Body ◽  
Callorhinus Ursinus ◽  
Metabolic Rates ◽  
Northern Fur Seal ◽  
Fur Seal

Young pinnipeds, born on land, must eventually enter the water to feed independently. The aim of this study was to examine developmental factors that might influence this transition. The ontogeny of metabolic rate and thermoregulation in northern fur seal, Callorhinus ursinus, pups was investigated at two developmental stages in air and water using open-circuit respirometry. Mean in-air resting metabolic rate (RMR) increased significantly from 113+/−5 ml O(2)min(−)(1) (N=18) pre-molt to 160+/−4 ml O(2)min(−)(1) (N=16; means +/− s.e.m.) post-molt. In-water, whole-body metabolic rates did not differ pre- and post-molt and were 2.6 and 1.6 times in-air RMRs respectively. Mass-specific metabolic rates of pre-molt pups in water were 2.8 times in-air rates. Mean mass-specific metabolic rates of post-molt pups at 20 degrees C in water and air did not differ (16.1+/−1.7 ml O(2)min(−)(1)kg(−)(1); N=10). In-air mass-specific metabolic rates of post-molt pups were significantly lower than in-water rates at 5 degrees C (18.2+/−1.1 ml O(2)min(−)(1)kg(−)(1); N=10) and 10 degrees C (19.4+/−1.7 ml O(2)min(−)(1)kg(−)(1); N=10; means +/− s.e.m.). Northern fur seal pups have metabolic rates comparable with those of terrestrial mammalian young of similar body size. Thermal conductance was independent of air temperature, but increased with water temperature. In-water thermal conductance of pre-molt pups was approximately twice that of post-molt pups. In-water pre-molt pups matched the energy expenditure of larger post-molt pups while still failing to maintain body temperature. Pre-molt pups experience greater relative costs when entering the water regardless of temperature than do larger post-molt pups. This study demonstrates that the development of thermoregulatory capabilities plays a significant role in determining when northern fur seal pups enter the water.

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