scholarly journals Reduced metabolism supports hypoxic flight in the high-flying bar-headed goose (Anser indicus)

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Jessica U Meir ◽  
Julia M York ◽  
Bev A Chua ◽  
Wilhelmina Jardine ◽  
Lucy A Hawkes ◽  
...  
Keyword(s):  
Heart Rate ◽  
Wind Tunnel ◽  
Metabolic Rate ◽  
Simulated Altitude ◽  
Initial Portion ◽  
Migratory Flight ◽  
O2 Extraction ◽  
Extreme Altitude ◽  
Anser Indicus ◽  
Mixed Venous

The bar-headed goose is famed for migratory flight at extreme altitude. To better understand the physiology underlying this remarkable behavior, we imprinted and trained geese, collecting the first cardiorespiratory measurements of bar-headed geese flying at simulated altitude in a wind tunnel. Metabolic rate during flight increased 16-fold from rest, supported by an increase in the estimated amount of O2 transported per heartbeat and a modest increase in heart rate. The geese appear to have ample cardiac reserves, as heart rate during hypoxic flights was not higher than in normoxic flights. We conclude that flight in hypoxia is largely achieved via the reduction in metabolic rate compared to normoxia. Arterial Po2 was maintained throughout flights. Mixed venous PO2 decreased during the initial portion of flights in hypoxia, indicative of increased tissue O2 extraction. We also discovered that mixed venous temperature decreased during flight, which may significantly increase oxygen loading to hemoglobin.

Heart rate and the rate of oxygen consumption of flying and walking barnacle geese (Branta leucopsis) and bar-headed geese (Anser indicus)

2002 ◽  
Vol 205 (21) ◽  
pp. 3347-3356 ◽  
Author(s):  
S. Ward ◽  
C. M. Bishop ◽  
A. J. Woakes ◽  
P. J. Butler
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Wind Tunnel ◽  
Migratory Birds ◽  
Free Living ◽  
Rate Of Oxygen Consumption ◽  
Barnacle Geese ◽  
Branta Leucopsis ◽  
Anser Indicus ◽  
The Relationship

SUMMARYWe tested the hypotheses that the relationship between heart rate(fH) and the rate of oxygen consumption(V̇O2) differs between walking and flying in geese and that fH and V̇O2 have a U-shaped relationship with flight speed. We trained barnacle geese Branta leucopsis (mean mass 2.1 kg) and bar-headed geese Anser indicus(mean mass 2.6 kg) to walk inside a respirometer on a treadmill and to fly in a wind tunnel with a respirometry mask at a range of speeds. We measured fH and V̇O2simultaneously during walking on the treadmill in five individuals of each species and in one bar-headed goose and four barnacle geese during flight in the wind tunnel. The relationships between fH and V̇O2 were significantly different between flying and walking. V̇O2 was higher,and the increment in V̇O2 for a given increase in fH was greater, for flying than for walking geese. The relationship between fH and V̇O2 of free-living barnacle geese during their natural migratory flights must differ from that measured in the wind tunnel, since the fH of wild migratory birds corresponds to values of V̇O2 that are unrealistically low when using the calibration relationship for our captive birds. Neither fH nor V̇O2 varied with flight velocity across the range of speeds over which the geese would fly sustainably.

Some consequences of body size

1984 ◽  
Vol 247 (4) ◽  
pp. H495-H507 ◽  
Author(s):  
L. E. Ford
Keyword(s):  
Heart Rate ◽  
Body Weight ◽  
Metabolic Rate ◽  
Muscle Power ◽  
Weight Ratio ◽  
Single Species ◽  
Hill Climbing ◽  
Proper Size ◽  
Higher Power ◽  
Metabolic Indices

The question of the proper size denominator for metabolic indices is addressed. Metabolic rate among different species is proportional to the 3/4 power of body weight, not surface area. Muscle power also varies with the 3/4 power of weight, suggesting that metabolic rate is determined mainly by muscle power. Power-to-weight ratio, specific metabolic rate, and a number of metabolic periods, including heart rate, all vary inversely with the 1/4 power of body weight. Thus the relative times required for physiological and pathological processes in different species may be estimated from the average resting heart rate for the species. There are not many small humans among athletic record holders in events involving acceleration and hill climbing, as would be expected if they had higher power-to-weight ratios. Thus the relationship between size and metabolic rate in different species should not be applied within the single species of humans. Evidence is reviewed showing that basal metabolic rate in humans is determined mainly by lean body mass.

Respiratory Metabolism During Pregnancy in the Guinea Pig

1957 ◽  
Vol 190 (3) ◽  
pp. 425-428 ◽  
Author(s):  
Richard M. Hoar ◽  
William C. Young
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Guinea Pig ◽  
Metabolic Rate ◽  
Adrenal Cortex ◽  
Guinea Pigs ◽  
Sharp Decrease ◽  
Zona Fasciculata ◽  
Respiratory Metabolism ◽  
Morphological Differences

Oxygen consumption and heart rate during pregnancy were measured in untreated, thyroxin-injected and thyroidectomized guinea pigs given I131. From impregnation until parturition, oxygen consumption increased 7.9% in untreated females. The increase continued until 5 days postpartum when a sharp decrease occurred. The increase is not accounted for by growth of the fetal mass. Comparable increases occurred in thyroxin-injected (16.2%) and thyroidectomized (11.9%) females, although the levels throughout were higher and lower, respectively, than in intact females. Heart rate did not increase. On the contrary, statistically significant decreases occurred in the untreated and thyroxin-injected females. Although the mechanism associated with the increased metabolic rate is not known, the possibility of thyroid participation would seem to be excluded. Involvement of the adrenal cortex is suggested by morphological differences in the cells of the zona fasciculata in pregnant and nonpregnant females and by evidence cited from other studies.

Regional circulatory responses to hypocapnia and hypercapnia in bar-headed geese

1986 ◽  
Vol 250 (3) ◽  
pp. R499-R504 ◽  
Author(s):  
F. M. Faraci ◽  
M. R. Fedde
Keyword(s):  
Blood Flow ◽  
Regional Blood Flow ◽  
Muscle Blood Flow ◽  
Pectoral Muscle ◽  
Blood Flows ◽  
Arterial Blood ◽  
Blood Flow Reduction ◽  
Extreme Altitude ◽  
Anser Indicus ◽  
O2 Delivery

To investigate mechanisms that may allow birds to tolerate extreme high altitude (hypocapnic hypoxia), we examined the effects of severe hypocapnia and moderate hypercapnia on regional blood flow in bar-headed geese (Anser indicus), a species that flies at altitudes up to 9,000 m. Cerebral, coronary, and pectoral muscle blood flows were measured using radioactive microspheres, while arterial CO2 tension (PaCO2) was varied from 7 to 62 Torr in awake normoxic birds. Arterial blood pressure was not affected by hypocapnia but increased slightly during hypercapnia. Heart rate did not change during alterations in PaCO2. Severe hypocapnia did not significantly alter cerebral, coronary, or pectoral muscle blood flow. Hypercapnia markedly increased cerebral and coronary blood flow, but pectoral muscle blood flow was unaffected. The lack of a blood flow reduction during severe hypocapnia may represent an important adaptation in these birds, enabling them to increase O2 delivery to the heart and brain at extreme altitude despite the presence of a very low PaCO2.

Diaphragm does not produce ammonia or lactate during high-intensity short-term exercise

1990 ◽  
Vol 259 (4) ◽  
pp. H1185-H1189 ◽  
Author(s):  
M. Manohar ◽  
A. S. Hassan
Keyword(s):  
Heart Rate ◽  
High Intensity ◽  
Work Of Breathing ◽  
Lactate Production ◽  
Exercise Heart Rate ◽  
Short Term ◽  
Energy Needs ◽  
Standard Procedures ◽  
O2 Extraction ◽  
Limb Muscles

To ascertain whether costal diaphragm engages in ammonia and lactate production (like limb muscles) during high-intensity short-term exercise, experiments were carried out on six healthy trained ponies in which phrenic venous catheters had been implanted 5-9 days earlier. Simultaneous anaerobically obtained blood samples from abdominal aorta and the phrenic vein at rest and during 4 min of exertion at 32 km/h and at a 7% grade were analyzed for blood-gas variables as well as lactate and ammonia concentrations using standard procedures. At rest, heart rate was 47 +/- 4 beats/min and the diaphragmatic O2 extraction was 26.5%. With exercise, heart rate rose to 218 +/- 6 beats/min, marked acidosis and hyperventilation occurred, and the diaphragmatic O2 extraction increased threefold (80.9%). Such exercise is known to dramatically increase the work of breathing as respiratory frequency and change in pleural pressure approach 138 +/- 4 breaths/min and 30 +/- 3 cmH2O, respectively. Despite the fact that phrenic-venous O2 tension of exercised ponies decreased to 15.5 +/- 0.6 Torr, the phrenic-venous lactate and ammonia concentrations did not exceed corresponding arterial values. These data thus revealed that the diaphragm is uniquely unlike limb muscles, which at high workloads readily engage in net ammonia and lactate production, and that the diaphragmatic energy needs during high-intensity short-term exercise are primarily met by aerobic metabolism.

scholarly journals Can offsetting the energetic cost of hibernation restore an active season phenotype in grizzly bears (Ursus arctos horribilis)?

2021 ◽  
Author(s):  
Heiko T. Jansen ◽  
Brandon Evans Hutzenbiler ◽  
Hannah R. Hapner ◽  
Madeline L. McPhee ◽  
Anthony M. Carnahan ◽  
...  
Keyword(s):  
Heart Rate ◽  
Insulin Sensitivity ◽  
Metabolic Rate ◽  
Ursus Arctos ◽  
Metabolic Effects ◽  
Energetic Cost ◽  
Grizzly Bears ◽  
Flux Analysis ◽  
Active Season ◽  
Ursus Arctos Horribilis

ABSTRACTHibernation is characterized by suppression of many physiological processes. To determine if this state is reversible in a non-food caching species, we fed hibernating grizzly bears (Ursus arctos horribilis) glucose for 10 days to replace 53% or 100% of the estimated minimum daily energetic cost of hibernation. Feeding caused serum concentrations of glycerol and ketones (ß-hydroxybutyrate) to return to active season levels irrespective of the amount of glucose fed. By contrast, free-fatty acids and indices of metabolic rate, such as general activity, heart rate, and strength of the daily heart rate rhythm and insulin sensitivity were restored to roughly 50% of active season levels. Body temperature was unaffected by feeding. To determine the contribution of adipose to these metabolic effects of glucose feeding we cultured bear adipocytes collected at the beginning and end of the feeding and performed metabolic flux analysis. We found a roughly 33% increase in energy metabolism after feeding. Moreover, basal metabolism before feeding was 40% lower in hibernation cells compared to fed cells or active cells cultured at 37°C, thereby confirming the temperature independence of metabolic rate. The partial suppression of circulating FFA with feeding likely explains the incomplete restoration of insulin sensitivity and other metabolic parameters in hibernating bears. Further suppression of metabolic function is likely an active process. Together, the results provide a highly controlled model to examine the relationship between nutrient availability and metabolism on the hibernation phenotype in bears.

scholarly journals Energy Cost of Running in an Arctic Fox, Alopex lagopus

2003 ◽  
Vol 117 (3) ◽  
pp. 430 ◽  
Author(s):  
Eva Fuglei ◽  
Nils A. Øritsland
Keyword(s):  
Heart Rate ◽  
Metabolic Rate ◽  
Energy Cost ◽  
The Arctic ◽  
Arctic Fox ◽  
Alopex Lagopus ◽  
Energy Cost Of Running ◽  
Radio Transmitters ◽  
The Relationship ◽  
Determine Effect

This work was conducted to determine effect of season and starvation on metabolic rate during running in the Arctic Fox (Alopex lagopus) on Svalbard (78°55’N, 11°56’E), Norway. Indirect calorimetry was used to measure metabolic rate of foxes running on a treadmill and heart rate was monitored using implanted radio transmitters. The relationship between heart rate and metabolic rate was also examined. Metabolic rate increased with running speed. In July the metabolic rate during running almost fitted general equations predicted for mammals, while it was up to 20% lower in January, indicating seasonal variation in metabolic rate. There was a significant positive linear relationship between heart rate and weight specific metabolic rate, suggesting that heart rate can be used as an indicator of metabolic rate. Starvation for 11 days decreased the net cost of running by 13% in January and 17% in July, suggesting that a starved fox runs more energetically efficient than when fed. Heart rate measured in July decreased by 27% during starvation. Re-feeding reversed the starvation-induced reduction in metabolic rate and heart rate during running almost up to post-absorptive levels. The present results are from one fox, and must be considered as preliminary data until further studies are conducted.

Intestinal capillary blood flow during metabolic hyperemia.

1979 ◽  
Vol 237 (6) ◽  
pp. E548 ◽  
Author(s):  
A P Shepherd
Keyword(s):  
Blood Flow ◽  
Metabolic Rate ◽  
Constant Pressure ◽  
Oxygen Demand ◽  
Capillary Density ◽  
Control Mechanisms ◽  
O2 Uptake ◽  
O2 Extraction ◽  
Circulatory Control ◽  
Parenchymal Cells

It has been postulated that local circulatory control mechanisms regulate the O2 flux to parenchymal cells by two vascular mechanisms: changes in blood flow that minimize capillary PO2 variations and changes in the density of the perfused capillary bed through which O2 extraction is regulated. To test this prediction, isolated loops of canine jejenum and ileum were perfused at either constant blood flow or constant pressure, and intraluminal glucose was used to increase metabolic rate. In the constant-flow series, glucose increased O2 extraction, O2 uptake, and rubidium extraction. Resistance fell when the metabolic rate was elevated. In the constant-pressure series, glucose increased blood flow, O2 extraction, O2 uptake, and capillary filtration coefficients. These results show that vascular resistance falls and that capillary density increases following an increase in oxygen demand. Thus, the glucose-stimulated gut loop seems to be a valid model of metabolic hyperemia, and its behavior would be difficult to reconcile with a purely myogenic theory of intestinal blood flow autoregulation.

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