scholarly journals Metabolic rate and plasma T3 in ad lib. fed and starved muskoxen

Rangifer ◽  
1994 ◽  
Vol 14 (2) ◽  
pp. 79 ◽  
Author(s):  
K.J. Nilssen ◽  
S.D. Mathiesen ◽  
A.S. Blix

Resting metabolic rate (RMR) in two 12 yrs., semidomesticated, female muskoxen was 0.86 ± 0.10 W • kg-1 in winter, and 1.74 ± 0.27 W • kg-1 in summer, (p<0.001). After 6 days of starvation RMR was down to 0.62 + 0.07 W • kg-1 and 0.77 ± 0.03 W • kg-1 (p<0.001) in winter and summer, respectively. RMR during starvation in winter was 19% below predicted RMR for animals of equal body mass. Standing RMR was significantly higher (p<0.01) than lying RMR. Winter plasma levels of T3 in both animals were 1-1 nmol • l-1 when food was freely available, and 1.4 nmol • l-1 after 6 days of starvation. Plasma concentration of T3 in another 8 free ranging semi-domesticated, female muskoxen aged 12 yrs. in March was 0.64 ± 0.20 nmol • l-1. Corrseponding value in August was 1.00 ± 0.10 nmol • l-1, being significantly higher (p<0.01) than the winter value.

1982 ◽  
Vol 60 (6) ◽  
pp. 1412-1416 ◽  
Author(s):  
Justin D. Congdon ◽  
Donald W. Tinkle

Metabolic rates of free-ranging Sceloporus graciosus (Sauria: Iguanidae) were measured during the summer using doubly labeled H2O. Adults of either sex and juveniles did not differ in field metabolic rates (0.26 mL CO2∙g−1∙h−1or 160 J∙g−1∙day−1). Field metabolic rates were 2.4 times the resting metabolic rate, and activity respiration was 3.1 times the resting metabolic rate at lizard activity temperatures. Activity accounted for 59% of the energy consumption due to respiration. Calculated rates of feeding indicated a 415 J∙day−1 deficit in metabolizable energy intake, and this was reflected in rate of loss of body mass throughout the study. Daily energy harvested by 200 lizards (31 kJ∙day−1), which approximates densities (per hectare) on the study area, would supply only 40% of the daily energy requirements of one insectivorous bird with similar body mass and activity level of a Phainopepla (79 kJ∙day−1).


2009 ◽  
Vol 87 (10) ◽  
pp. 956-964 ◽  
Author(s):  
Michael J. Sheriff ◽  
J. R. Speakman ◽  
L. Kuchel ◽  
S. Boutin ◽  
M. M. Humphries

The hypothesis that cold air temperatures (Ta) constrain the metabolic diversity of high-latitude endotherms is based on the observation among birds and mammals that mean field metabolic rate (FMR) increases, whereas the variability of FMR decreases, from the warm tropics to the cold poles. However, there is a paucity of FMR measurements from above 60° latitude and below 0 °C. We measured the daily energy expenditure of a high-latitude population of free-ranging snowshoe hares ( Lepus americanus Erxleben, 1777) in Yukon, Canada, in winter (Ta-mean = –16.4 °C) and in autumn (Ta-mean = 0.5 °C). Doubly labelled water measures of FMR were approximately 20% lower in winter than in autumn, and were a similar, low multiple of resting metabolic rate in both seasons (2.04 and 1.94, respectively). The mass-corrected FMR of snowshoe hares in winter was only half the value predicted by extrapolating the relationship between FMR and Ta > 0 to –16.4 °C. These results contribute to an emerging pattern of a reversal in the relationship between FMR and Ta in free-ranging mammals from negative above 0 °C to positive below 0 °C. We refer to the positive, low Ta portion of this relationship as the cold shoulder, and suggest that it may reflect the general necessity for free-ranging mammals to use behavioural and (or) physiological means to conserve energy during long winters when cold conditions coincide with resource scarcity.


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

2019 ◽  
Vol 72 (9-10) ◽  
pp. 272-279
Author(s):  
Danijel Slavic ◽  
Dea Karaba-Jakovljevic ◽  
Andrea Zubnar ◽  
Borislav Tapavicki ◽  
Tijana Aleksandric ◽  
...  

Introduction. The difference between 24-hour daily energy intake and total daily energy expenditure determines whether we lose or gain weight. The resting metabolic rate is the major component of daily energy expenditure, which depends on many different factors, but also on the level of physical activity. The aim of the study was to determine anthropometric and metabolic parameters of athletes engaged in different types of training, to compare obtained results and to examine whether there are statistically significant differences among them. Material and Methods. The study included a total of 42 young male athletes divided into two groups. The first group included 21 athletes who were predominantly engaged in aerobic type of training, and the other group of 21 athletes in anaerobic type of training. Anthropometric measurements were taken and resting metabolic rate was assessed using the indirect calorimetry method. The results were statistically analyzed and the differences in parameters between the two groups were compared. Results. Statistically significant differences were established in total body mass, amount of fat-free mass and muscle mass, body mass index, as well as in the relative metabolic indices between two groups of subjects. Conclusion. The percentage of fat-free body mass has the greatest impact on the resting metabolic rate. The rate of metabolic activity of this body compartment is higher in athletes engaged in aerobic than in athletes engaged in anaerobic type of training.


2020 ◽  
Author(s):  
Ghazaleh Khalili ◽  
Atieh Mirzababaei ◽  
Farideh Shiraseb ◽  
Khadijeh Mirzaei

Abstract Objective: Obesity as a worldwide phenomenon is a multifactorial condition. Healthy diets have effect on obesity related factors like resting metabolic rate (RMR). In present study, we investigate association between adherence to modified Nordic diet and RMR among overweight and obese participants.Methods: We enrolled 404 overweight and obese (BMI ≥25 kg/m2) women aged 18-48 years in this cross-sectional study. For each participant anthropometrics measurements, biochemical tests and blood pressure were evaluated. RMR was measured by indirect calorimetry. RMR/kg was also measured. Modified Nordic diet score was measured using a validated 147-item food frequency questionnaire (FFQ).Results: Among all participants, the mean and standard deviation (SD) for age and body mass index (BMI) were 36.67 years (SD=9.10) and 31.26 kg/m2 (SD=4.29). There was a significant association between RMR/kg status and age, body mass index (BMI), RMR (P<0.001), respiratory quotient (RQ), fat percentage (P= 0.01), systolic blood pressure (SBP) (P= 0.03), and diastolic blood pressure (DBP) (P= 0.04), after adjustment for age, BMI, energy intake and physical activity. Participants with the highest adherence to modified Nordic diet had lower odds of hypometabolic status after adjusting for confounders and it was significant (odds ratio (OR) = 3.15, 95% CI= 0.97-10.15, P=0.05).Conclusions: The present results indicate that adherence to modified Nordic diet is associated with lower odds of hypometabolic status in overweight and obese women. However more studies are needed to confirm our findings.


The Condor ◽  
2006 ◽  
Vol 108 (1) ◽  
pp. 166-177 ◽  
Author(s):  
Michael R. Miller ◽  
John McA. Eadie

AbstractWe examined the allometric relationship between resting metabolic rate (RMR; kJ day−1) and body mass (kg) in wild waterfowl (Anatidae) by regressing RMR on body mass using species means from data obtained from published literature (18 sources, 54 measurements, 24 species; all data from captive birds). There was no significant difference among measurements from the rest (night; n = 37), active (day; n = 14), and unspecified (n = 3) phases of the daily cycle (P > 0.10), and we pooled these measurements for analysis. The resulting power function (aMassb) for all waterfowl (swans, geese, and ducks) had an exponent (b; slope of the regression) of 0.74, indistinguishable from that determined with commonly used general equations for nonpasserine birds (0.72–0.73). In contrast, the mass proportionality coefficient (b; y-intercept at mass = 1 kg) of 422 exceeded that obtained from the nonpasserine equations by 29%–37%. Analyses using independent contrasts correcting for phylogeny did not substantially alter the equation. Our results suggest the waterfowl equation provides a more appropriate estimate of RMR for bioenergetics analyses of waterfowl than do the general nonpasserine equations. When adjusted with a multiple to account for energy costs of free living, the waterfowl equation better estimates daily energy expenditure. Using this equation, we estimated that the extent of wetland habitat required to support wintering waterfowl populations could be 37%–50% higher than previously predicted using general nonpasserine equations.


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