Doubly labelled water measurements of field metabolic rate in White-tailed Ptarmigan: variation in background isotope abundances and effect on CO2 production estimates

1994 ◽  
Vol 72 (11) ◽  
pp. 1967-1972 ◽  
Author(s):  
Donald W. Thomas ◽  
Kathy Martin ◽  
Hélène Lapierre

We measured background 2H and 18O abundances and field metabolic rate (FMR) for White-tailed Ptarmigan (Lagopus leucurus) above 3600 m elevation in the Colorado Rocky Mountains between May and July. 18O abundances ranged from 1982.4 to 2018.6 ppm [Formula: see text], while 2H abundance ranged from 142.8 to 154.0 ppm [Formula: see text]. Mean 2H abundance followed closely (−0.3 ppm deviation) the level predicted by Tatner's empirical model relating 2H and ambient temperature. However, 18O was more enriched than predicted (+3.4 ppm), which may reflect 18O fractionation in the plant diet. FMR, measured by means of the doubly labelled water method, ranged from 206.4 to 442.7 kJ/d and was not related to body mass. However, for males, FMR was significantly and positively related to age. Because of high variation in background isotope levels, the use of mean 2H and 18O background abundances instead of individual backgrounds would introduce a mean error of 7.1% (range −8.9 to +11.4%) in calculations of CO2 production and FMR.

2000 ◽  
Vol 48 (3) ◽  
pp. 225 ◽  
Author(s):  
Lesley A. Gibson ◽  
Ian D. Hume

Water and energy requirements of free-living male and female greater bilbies (Macrotis lagotis) were measured over two summers and two winters on Astrebla Downs National Park in far south-western Queensland, Australia, by means of the doubly labelled water method. Mean water influx rate of the bilby (mean body mass: summer 928 g; winter 848 g) did not differ between summer (63.1 mL day–1) and winter (53.1 mL day–1), but mean field metabolic rate was significantly higher during summer (617.2 kJ day–1) than in winter (480.3 kJ day–1). The comparatively low water influx rate of the bilby (significantly lower than that predicted for a 887-g marsupial: P < 0.001) indicated that bilbies have the ability to conserve water in the wild. In contrast, field metabolic rate of the bilby did not differ significantly from that predicted for a marsupial of its body mass (P = 0.999). Bilbies were able to obtain sufficient food and water to satisfy energy and water requirements in three out of the four study periods. However, they were in negative energy and water balance during one study period, suggesting that they are susceptible to nutrient and water stress. The relatively low body fat stores of bilbies in the wild also indicate that they are vulnerable to periods of low food availability. The metabolic strategies of the bilby are only partly suggestive of adaptation to arid conditions.


2013 ◽  
Vol 82 (5) ◽  
pp. 1009-1020 ◽  
Author(s):  
Lawrence N. Hudson ◽  
Nick J. B. Isaac ◽  
Daniel C. Reuman

1996 ◽  
Vol 44 (5) ◽  
pp. 445 ◽  
Author(s):  
WW Weathers ◽  
DC Paton ◽  
RS Seymour

Field metabolic rate (FMR) and water influx of New Holland honeyeaters (Phylidonyris novaehollandiae), eastern spinebills (Acanthorhynchus tenuirostris) and a crescent honeyeater (P. pyrrhoptera) were measured by the doubly labelled water technique. New Holland honeyeaters had just finished breeding and were beginning their summer moult. They ranged in mass from 15.4 to 21.0 g (mean = 17.3 g, n = 12) and had FMRs averaging 8.8 mt CO2 g(-1) h(-1) or 77.6 kJ day(-1), which was 2.8 times their measured basal metabolic rate (BMR). Their water influx rate averaged 10.7 mL day(-1). Eastern spinebills were still feeding young and had yet to begin moulting. They ranged in mass from 8.0 to 10.7 g (mean = 9.7 g, n = 6), had FMRs averaging 10.9 mL CO2 g(-1) h(-1) or 52.9 kJ day(-1) (2.5 times their measured BMR), and had an average water influx rate of 8.7 mL day(-1). FMR and water influx of a single 14.6-g crescent honeyeater, which was in late primary moult, were 75.9 kJ day(-1) (2.7 times measured BMR) and 12.5 mL day(-1). The FMR of New Holland honeyeaters varied inversely with mean standard operative temperature (T-es) calculated for values of T-es below 20 degrees C as follows: FMR (kJ day(-1)) = 134 - 5.47 T-es (n = 12, r(2) = 0.52). Honeyeater FMRs were much lower than would be predicted allometrically for hummingbirds of the same mass, reflecting the honeyeaters' low-cost foraging tactic of consuming nectar while perched.


The Condor ◽  
2001 ◽  
Vol 103 (2) ◽  
pp. 376-380 ◽  
Author(s):  
Avner Anava ◽  
Michael Kam ◽  
Amiram Shkolnik ◽  
A. Allan Degen

Abstract Arabian Babblers (Turdoides squamiceps; adult body mass 65–75 g) are territorial, cooperatively breeding passerines that inhabit hot, dry deserts. Groups include breeding adults and helpers and generally consist of 3 to 5 individuals (range 2 to 22). All group members provision nestlings at similar rates, and individual visitation rates decline with increasing group size. Consequently, we predicted that the field metabolic rate (FMR) of individuals provisioning nestlings would decrease with increasing group size. To test this prediction, we determined FMR of primary female, primary male, female helper and male helper babblers in different sized groups provisioning nestlings. Field metabolic rate of primary females, but not other classes, decreased linearly with group size. This energy savings could allow primary females in larger groups to start a new nest more quickly. FMR for all babblers was 61% to 66% of the value predicted for a passerine of its body mass provisioning nestlings and was 3.11 × BMR, similar to the mean value of 3.13 × BMR reported for a number of terrestrial species.


1988 ◽  
Vol 36 (3) ◽  
pp. 293 ◽  
Author(s):  
KA Nagy ◽  
AK Lee ◽  
RW Martin ◽  
MR Fleming

Field metabolic rates (FMRs) and rates of water flux in free-ranging fat-tailed dunnarts, Sminthopsis crassicaudata, were measured during spring (late October) using doubly labelled water. Feeding rates were estimated on the basis of water and energy fluxes. FMRs averaged 68.7 kJ d-' in adults (mean body mass= 16.6 g), and were 29.2 kJ d-' in juveniles (6.1 g). These FMRs are 6.6 times basal metabolic rate (BMR), and are much higher than the hypothetical maxima of four to five times BMR. Other dasyurid marsupials also have high FMR/BMR ratios, but so does a small petaurid marsupial. S. crassicaudata consumed 80-90% of its body mass in arthropods each day. The diet of arthropods apparently provided enough water for the animals to maintain water balance without drinking during this study.


1988 ◽  
Vol 36 (2) ◽  
pp. 159 ◽  
Author(s):  
R Gales ◽  
B Green ◽  
C Stahel

Levels of circulating triglycerides and cholesterol in moulting little penguins in Tasmania were measured before, and throughout the moult. Levels at the initiation of moult were similar to those in breeding birds but increased by 2.5 times (triglycerides) and 1.8 times (cholesterol) during the moult. Water flux rates and field metabolic rate (FMR) were measured throughout moult with tritiated and doubly labelled water. TBW ranged from 54 to 70% body weight and increased during moult. Water influx rates were significantly correlated with rate of weight change. Mean FMR of moulting little penguins was 657 kJ kg-' day-', or 1.5 times basal metabolic rate (BMR), and there was no difference between sites or sexes. The water influx rates of birds foraging immediately after moult were 11 times higher than in moulting birds. The energy required to sustain a moulting little penguin is 15% higher than that required for a resting, non-moulting penguin. Although the cost of moult is elevated above BMR, the main energetic expense is met during the pre-moult foraging period when birds must consume enough food to ensure that they lay down sufficient fat reserves to sustain the moult.


1994 ◽  
Vol 76 (4) ◽  
pp. 1594-1599 ◽  
Author(s):  
C. Saiki ◽  
T. Matsuoka ◽  
J. P. Mortola

Previous studies have indicated that the hypometabolic response to hypoxia depends on ambient temperature (Ta), being more pronounced in the cold. If metabolic rate were an important contributor to the level of ventilation (VE), the magnitude of the hyperpneic response to hypoxia should also depend on Ta. We tested this hypothesis on adult conscious male rats. In normoxia, a drop in Ta from 25 to 10 degrees C increased O2 consumption and CO2 production (VO2 and VCO2, respectively, measured by an open-flow technique) and VE (measured with the barometric method) by 80 and 60%, respectively, with no changes in blood gases. At both Ta, hypoxia (10% inspired O2, 33–35 Torr arterial PO2) induced the same degree of hyperventilation, i.e., the same drop in arterial PCO2 (about -13 Torr). The hyperventilation at 25 degrees C Ta was achieved exclusively by an increase in VE, whereas at 10 degrees C Ta the hyperpnea was minimal (+15%) and accompanied by a drop (-30%) in VO2 and VCO2. Diaphragmatic electromyograms confirmed the VE results. Changes in blood pressure were similar at both Ta. Addition of 3% CO2 to the inspired air further increased VE, indicating that the hypoxic rat was not breathing at its maximal VE at either Ta. We conclude that, in the rat, changes in metabolic rate play an important role in the VE response to hypoxia and that Ta influences the response because of its effect on the degree of hypoxic hypometabolism.


2000 ◽  
Vol 203 (10) ◽  
pp. 1561-1572 ◽  
Author(s):  
R.L. Nudds ◽  
D.M. Bryant

Many small birds perform short flights, for which take-offs, ascents and descents form a large component of the total flight time and which are characterised by low airspeeds. Using the doubly-labelled water technique, zebra finches Taeniopygia guttata engaging in repeated short flights were found to expend 13.65 kJ more than ‘non-flying’ controls, which equated to a flight expenditure of 27.8 times their basal metabolic rate. This is over three times the predicted flight expenditure derived from existing aerodynamic models. These data were used to determine a coefficient (0.11) for converting the mechanical power derived from aerodynamic models into metabolic power. An equation is presented, based on body mass, which can be used to predict the costs of short flights in ecological and behavioural studies of birds.


2016 ◽  
Vol 38 (4) ◽  
pp. 361 ◽  
Author(s):  
Adam J. Munn ◽  
Yohannes Alemseged ◽  
Catharina Vendl ◽  
Mathew Stewart ◽  
Keith Leggett

Details of the energy (food) requirements of domestic herbivores are essential for predicting grazing pressures and subsequent ecological impacts on rangelands. However, these details are lacking for some of the more recently introduced sheep breeds to Australia, such as the Dorper breed sheep, which are principally meat sheep, and it is uncertain how they compare with the traditional Merino, a wool-breed, sheep. We used the doubly labelled water method to compare the field metabolic rate and water turnover rate of Dorpers and Merinos grazing together in a small holding paddock in a typical rangeland environment. We found no significant differences in field metabolic rate (Dorpers 481 ± 125 kJ and Merinos 500 ± 109 kJ kg–0.73 day–1) or water turnover rate (Dorpers 397 ± 57 mL and Merinos 428 ± 50 mL kg–0.8 day–1). As such we conclude that under controlled conditions with limited movement and ready access to feed and water, dry sheep equivalent of 1 is appropriate for Dorpers (that is, one Dorper ewe had a grazing requirement equal to one standard, dry Merino wether). However, we also found that the field metabolic rate for Merinos under these conditions was only around half that measured in published studies for animals ranging freely in a large paddock system. This suggests that more work is needed to fully appreciate the energetic and grazing impacts of Dorpers versus Merinos under more realistic grazing conditions (e.g. large paddock systems) where feed and water are more spread. It also highlights limitations of the current dry sheep equivalent rating system, which has been derived from laboratory measures of sheep metabolic rates.


2018 ◽  
Vol 192 (4) ◽  
pp. 518-524 ◽  
Author(s):  
Daniel E. Naya ◽  
Hugo Naya ◽  
Craig R. White

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