Seasonal variation in body mass and blood oxygen carrying capacity of the superb fairy-wren (Malurus cyaneus)

2002 ◽  
Vol 50 (3) ◽  
pp. 313 ◽  
Author(s):  
J. Box ◽  
A. Lill ◽  
J. Baldwin
Keyword(s):  
Body Mass ◽  
Carrying Capacity ◽  
Oxygen Delivery ◽  
Blood Oxygen ◽  
Additional Energy ◽  
Blood Haemoglobin ◽  
Malurus Cyaneus ◽  
Energy Challenge ◽  
Oxygen Carrying Capacity ◽  
Winter Fattening

The responses of small birds to many seasonal energy challenges include enhancement of aspects of aerobic metabolism, sometimes involving an increase in the rate of oxygen delivery to the metabolising tissues. One such mechanism that enhances oxygen delivery seasonally is an increase in blood oxygen carrying capacity. This response is enhanced in birds because of their rapid erythrocyte turnover rate. Some small birds have also evolved winter fattening, which helps them to meet the energy challenge presented by winter conditions. Such adaptations, while well documented for North Temperate birds, have received little attention in birds inhabiting temperate Australia. Over a two-year period, we examined seasonal changes in mass, an approximate indicator of fattening, and the parameters determining blood oxygen carrying capacity in a population of superb fairy-wrens (Malurus cyaneus) in outer Melbourne, Australia. Body mass did not vary significantly seasonally, but haematocrit and whole blood haemoglobin were significantly higher in the breeding season than at other times of year and the erythrocyte count was significantly higher in spring than in autumn. We conclude that the failure of the fairy-wrens to increase mass in winter (i.e. show marked winter fattening) was probably due to the comparative mildness of the climate and to the known fitness costs of fat storage. The significant 18% increase in blood oxygen carrying capacity in spring probably helped the birds to meet the additional energy requirements of breeding, particularly the likely increase in flight activity. However, given the magnitude of the increase, other mechanisms must have been involved in meeting breeding costs. The seasonal peak in blood oxygen carrying capacity did not coincide with the time when moulting was most pronounced.

Variation during breeding in parameters that influence blood oxygen carrying capacity in shearwaters

2000 ◽  
Vol 48 (4) ◽  
pp. 347 ◽  
Author(s):  
Cristina Davey ◽  
Alan Lill ◽  
John Baldwin
Keyword(s):  
Carrying Capacity ◽  
Energy Demand ◽  
Blood Parameters ◽  
Aerobic Metabolism ◽  
Egg Laying ◽  
Main Trend ◽  
Breeding Cycle ◽  
Blood Oxygen ◽  
Pattern Of Variation ◽  
Oxygen Carrying Capacity

Parameters that influence blood oxygen carrying capacity (whole-blood haemoglobin content, haematocrit and red blood cell count) were measured in samples of 30 breeding, adult short-tailed shearwaters (Puffinus tenuirostris) on Phillip Island, Victoria at seven key stages of their reproductive cycle. The aim of the investigation was to determine whether variation in blood oxygen carrying capacity during the birds’ 7-month breeding cycle was correlated with variation in the energy demands they experienced or was an incidental by-product of other physiological changes. All the blood parameters varied significantly during breeding, but the pattern of variation was only partly correlated with the likely pattern of changing energy demand imposed on parents by their schedule of breeding activities. The main trend conceivably related to energy demand was that significantly higher values were recorded for these blood parameters during the nestling stage than earlier in the breeding cycle. This could have reflected the high costs of the very long foraging trips undertaken by parents feeding nestlings, but it could also have occurred in preparation for the long migration undertaken soon after breeding finished. It involved an ~10% increase in blood oxygen carrying capacity above the lowest mean value recorded during the breeding cycle and so other mechanisms must also be employed to achieve the increase in aerobic metabolism likely to be required at this stage. The lack of adjustment of blood oxygen carrying capacity to energy demand early in the breeding cycle suggests that either oxygen delivery was not a rate-limiting process for aerobic metabolism at that time or that delivery was enhanced through other mechanisms. At egg laying, females had a lower haematocrit and erythrocyte count than males, which could be attributable to either estrogenic suppression of erythropoiesis or an increase in osmotic pressure of the blood associated with yolk synthesis. Immature, non-breeding birds attending the colony were of similar mass to adults, but did not show the increase in the parameters determining blood oxygen carrying capacity that occurred in adults later in the breeding cycle. Factors other than changing energy requirements (dehydration, burrow hypoxia and differential responsiveness to capture stress) that might have influenced the pattern of variation in blood oxygen carrying capacity of adults during breeding are discussed.

Activity-related variation in blood parameters associated with oxygen transport and chronic stress in little penguins

2007 ◽  
Vol 55 (4) ◽  
pp. 249 ◽  
Author(s):  
Louise Mortimer ◽  
Alan Lill
Keyword(s):  
Chronic Stress ◽  
Body Condition ◽  
Carrying Capacity ◽  
Condition Index ◽  
Blood Parameters ◽  
Body Condition Index ◽  
Stress Indicators ◽  
Nutrient Demand ◽  
Blood Haemoglobin ◽  
Oxygen Carrying Capacity

Some birds facing energy ‘bottlenecks’ display elevated oxidative metabolism and oxygen delivery to tissues and could be particularly susceptible to chronic stress. We examined whether there was evidence for such trends in little penguins (Eudyptula minor) over the period from breeding to the post-moulting stage and particularly during the onshore moult-fast. Penguin parents contribute equally to incubation, brooding and brood provisioning. A few weeks post-breeding, adults undergo a protracted, terrestrial moult-fast and then make brief visits to the colony during the post-moulting stage. Provisioning nestling(s) and moulting could theoretically be particularly energetically and nutritionally demanding. We determined for adults whether mass, a body condition index and blood parameters influencing vascular oxygen carrying capacity (hematocrit, Hct; whole blood haemoglobin, Hb) and indicating chronic stress (leukocyte count, WBC; heterophil/lymphocyte ratio, H/L) varied from August to May in a manner reflecting likely variation in energy and nutrient demand. Female mass and body condition index decreased significantly between the incubation and guard stages, before returning to incubation levels between the guard and post-guard nestling stages. Both parameters declined to their lowest levels between the post-guard and moult stages, before increasing to levels comparable with those during nestling care between the moult and post-moult stages. Blood parameters in both sexes exhibited temporal variation similar to that in female mass and body condition index, declining to their lowest levels during moult and increasing after the moult to levels comparable with those during breeding. Results indicated that the period of most intense provisioning of nestlings was associated with a decrease in blood oxygen carrying capacity, but no pronounced change in chronic stress indicators. However, the penguin’s moult-fast involved a loss of female body condition and, in both sexes, a reduction in body mass, vascular oxygen carrying capacity and possibly specific immune competence. Thus, regulation of human disturbance in accessible little penguin colonies may be particularly important during moult.

Hematological Aspects of the Thermoacclimatory Process in the Rainbow Trout, Salmo gairdneri

1967 ◽  
Vol 24 (11) ◽  
pp. 2267-2281 ◽  
Author(s):  
Mary Anne DeWilde ◽  
A. H. Houston
Keyword(s):  
Rainbow Trout ◽  
General Problem ◽  
Carrying Capacity ◽  
Packed Cell Volume ◽  
Salmo Gairdneri ◽  
Blood Oxygen ◽  
Hemoglobin Content ◽  
Oxygen Capacity ◽  
Higher Temperature ◽  
Oxygen Carrying Capacity

The blood oxygen capacity of the rainbow trout has been investigated as a function of thermal acclimation in terms of erythrocyte abundance, packed cell volume, hemoglobin concentrations, and mean erythrocytic volume and hemoglobin content. Fish at the lower acclimation temperatures employed (3, 7 C) were characterized by relatively low erythrocyte counts, hematocrits, and hemoglobin levels. Mean erythrocyte volumes tended to be relatively high, whereas mean erythrocytic hemoglobin content was somewhat below that typical of the higher temperature groups. In general, animals held at intermediate temperatures (11, 14, 17 C) showed significant increases in oxygen-carrying capacity by comparison with cold-acclimated fish. Finally trout at 21 C typically had larger numbers of somewhat smaller red cells, more hemoglobin, and higher levels of hemoglobin per erythrocyte than either the low- or intermediate-temperature fish. Significant differences were observed between summer and fall–winter series of trout, particularly with respect to hemoglobin levels. The results are discussed in relation to the general problem of respiratory thermoadaptation.

Chronic hypoxia and the cerebral circulation

2006 ◽  
Vol 100 (2) ◽  
pp. 725-730 ◽  
Author(s):  
Kui Xu ◽  
Joseph C. LaManna
Keyword(s):  
Blood Flow ◽  
Carrying Capacity ◽  
Hemoglobin Concentration ◽  
Capillary Density ◽  
Hypoxic Exposure ◽  
Blood Oxygen ◽  
Brain Capillary ◽  
Blood Flow Increase ◽  
Time Courses ◽  
Oxygen Carrying Capacity

Exposure to mild hypoxia elicits a characteristic cerebrovascular response in mammals, including humans. Initially, cerebral blood flow (CBF) increases as much as twofold. The blood flow increase is blunted somewhat by a decreasing arterial Pco2 as a result of the hypoxia-induced hyperventilatory response. After a few days, CBF begins to fall back toward baseline levels as the blood oxygen-carrying capacity is increasing due to increasing hemoglobin concentration and packed red cell volume as a result of erythropoietin upregulation. By the end of 2 wk of hypoxic exposure, brain capillary density has increased with resultant decreased intercapillary distances. The relative time courses of these changes suggest that they are adjusted by different control signals and mechanisms. The CBF response appears linked to the blood oxygen-carrying capacity, whereas the hypoxia-induced brain angiogenesis appears to be in response to tissue hypoxia.

scholarly journals Reduction of Oxygen-Carrying Capacity Weakens the Effects of Increased Plasma Viscosity on Cardiac Performance in Anesthetized Hemodilution Model

2012 ◽  
Vol 2012 ◽  
pp. 1-9
Author(s):  
Surapong Chatpun ◽  
Pedro Cabrales
Keyword(s):  
Cardiac Output ◽  
Carrying Capacity ◽  
Oxygen Delivery ◽  
Maximum Rate ◽  
Systolic Pressure ◽  
Pressure Change ◽  
Plasma Viscosity ◽  
Cardiac Performance ◽  
Dextran 70 ◽  
Oxygen Carrying Capacity

We investigated the effects of reduced oxygen-carrying capacity on cardiac function during acute hemodilution, while the plasma viscosity was increased in anesthetized animals. Two levels of oxygen-carrying capacity were created by 1-step and 2-step hemodilution in male golden Syrian hamsters. In the 1-step hemodilution (1-HD), 40% of the animals' blood volume (BV) was exchanged with 6% dextran 70 kDa (Dx70) or dextran 2000 kDa (Dx2M). In the 2-step hemodilution (2-HD), 25% of the animals' BV was exchanged with Dx70 followed by 40% BV exchanged with Dx70 or Dx2M after 30 minutes of first hemodilution. Oxygen delivery in the 2-HD group consequently decreased by 17% and 38% compared to that in the 1-HD group hemodiluted with Dx70 and Dx2M, respectively. End-systolic pressure and maximum rate of pressure change in the 2-HD group significantly lowered compared with that in the 1-HD group for both Dx70 and Dx2M. Cardiac output in the 2-HD group hemodiluted with Dx2M was significantly higher compared with that hemodiluted with Dx70. In conclusion, increasing plasma viscosity associated with lowering oxygen-carrying capacity should be considerably balanced to maintain the cardiac performance, especially in the state of anesthesia.

Effects of Venesection on Leg Blood Flow in Claudicants with High-Normal Haematocrit

1988 ◽  
Vol 33 (4) ◽  
pp. 298-299 ◽  
Author(s):  
A.R. Turner ◽  
G.D.O. Lowe ◽  
C.D. Forbes ◽  
J. G. Pollock
Keyword(s):  
Blood Flow ◽  
Intermittent Claudication ◽  
Carrying Capacity ◽  
Blood Viscosity ◽  
Oxygen Delivery ◽  
Peak Flow ◽  
Haemoglobin Concentration ◽  
Leg Blood Flow ◽  
Calf Blood Flow ◽  
Oxygen Carrying Capacity

Patients with intermittent claudication frequently have high-normal levels of haematocrit and hence blood viscosity, which may contribute to decreased calf blood flow on exercise, and hence to the symptom of claudication. Reduction in haematocrit and viscosity by serial venesection in eight patients with stable claudication and high-normal haematocrit (mean 0.50) was performed, and the effects on claudication, calf blood flow, and calf oxygen delivery were studied. Following reduction in haematocrit to low-normal levels (mean 0.44), resting calf blood flow was unchanged; peak flow after ischaemic exercise increased slightly (+17%), but peak oxygen delivery (peak flow × haemoglobin concentration) was unchanged. Hence any increase in calf blood flow in the symptomatic leg is balanced by a decrease in oxygen-carrying capacity after venesection. No increase in claudication time would therefore be expected, and none was observed in the present study.

Acute Cardiovascular and Hematologic Changes After a Single Transfusion Demonstrate Sex Differences in Chronically Transfused Sickle Cell Anemia Patients

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2138-2138
Author(s):  
Jon Detterich ◽  
Roberta Miyeko Kato ◽  
Ani Dongelyan ◽  
Adam Bush ◽  
Herbert J. Meiselman ◽  
...  
Keyword(s):  
Platelet Count ◽  
Cardiac Index ◽  
Vascular Resistance ◽  
Carrying Capacity ◽  
Oxygen Delivery ◽  
Reticulocyte Count ◽  
Free Hemoglobin ◽  
Hemoglobin S ◽  
Oxygen Carrying Capacity

Abstract Abstract 2138 Chronic transfusion therapy (CTT) is a mainstay for stroke prophylaxis in sickle cell anemia. Long-term changes with transfusion include decreased hemoglobin S% and hemolysis resulting in decreased plasma free hemoglobin. Long-term benefits are well documented, however, patients on CTT continue to suffer from acute crises. The acute effects of each transfusion are not well known but might include improved oxygen carrying capacity secondary to increased hematocrit, reducing demands for high cardiac output. But, the increased hematocrit and oxygen carrying capacity is at the cost of increased viscosity and resistance to blood flow. Despite long-term benefits, acute complications continue to plague this patient population and could be due to acute rheologic changes with transfusion. We hypothesized that transfusion would acutely improve tissue oxygen delivery despite increasing blood viscosity and vascular resistance. To test this hypothesis, we prospectively examined patients on CTT immediately pre transfusion and again 12–120 hours post transfusion. Hemodynamics were tested by measuring blood pressure, heart rate and cardiac function by echocardiography. Tissue oxygen delivery was assessed using echocardiographic estimates of cardiac output, pulse oximetry and oxygen carrying capacity as well as near infrared spectroscopy (NIRS). We obtained basic hematology and metabolic labs in addition to markers of inflammation, hemolysis and amino acid profile at both visits. Male and female patients were equally represented with similar average age. The reasons for starting transfusion as well as medication profiles were similar between sexes. Comparable changes in hemoglobin, hematocrit, reticulocyte count and hemoglobin S with transfusion were observed in all patients. However, when pre transfusion levels of free hemoglobin, hemoglobin S%, platelet count and reticulocyte count were examined with regard to timing from the previous transfusion, males had faster recovery of endogenous marrow activity and increased hemolysis, producing higher average hemoglobin S%, reticulocyte count, platelet count and free hemoglobin levels (figure 1). In males, transfusion decreased heart rate, stroke volume, and cardiac index while estimates for pulmonary and systemic vascular resistance rose, culminating in decreased oxygen delivery. In contrast, stroke volume and cardiac index were preserved in women following transfusion, while systemic and pulmonary vascular resistance did not change such that oxygen delivery improved 16%. NIRS measurements assessing tissue oxygenation confirmed the differences seen using echocardiography and oxygen carrying capacity estimates(figure 2).Figure 1Figure 1. Figure 2Figure 2. Increased endogenous marrow activity in males, resulting in higher pre-transfusion reticulocyte count, hemoglobin S%, platelet count and free hemoglobin might account for the exaggerated reduction in cardiac index, as well as increased systemic and pulmonary vascular resistance with transfusion. In addition, the faster recovery of hemoglobin S% and hemolysis likely confers increased risk of vascular complications in male patients despite chronic transfusion therapy. Disclosures: Wood: Novartis: Research Funding; Ferrokin Biosciences: Consultancy; Cooleys Anemia Foundation: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.

scholarly journals Simultaneous exposure to nitrate and low pH reduces the blood oxygen-carrying capacity and functional performance of a freshwater fish

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Daniel F Gomez Isaza ◽  
Rebecca L Cramp ◽  
Craig E Franklin
Keyword(s):  
Carrying Capacity ◽  
Functional Performance ◽  
Swimming Performance ◽  
Low Ph ◽  
Blood Oxygen ◽  
Aerobic Scope ◽  
Simultaneous Exposure ◽  
Post Exercise ◽  
Oxygen Carrying Capacity ◽  
Post Exercise Recovery

Abstract Human activities present aquatic species with numerous of environmental challenges, including excessive nutrient pollution (nitrate) and altered pH regimes (freshwater acidification). In isolation, elevated nitrate and acidic pH can lower the blood oxygen-carrying capacity of aquatic species and cause corresponding declines in key functional performance traits such as growth and locomotor capacity. These factors may pose considerable physiological challenges to organisms but little is known about their combined effects. To characterise the energetic and physiological consequences of simultaneous exposure to nitrate and low pH, we exposed spangled perch (Leiopotherapon unicolor) to a combination of nitrate (0, 50 or 100 mg L−1) and pH (pH 7.0 or 4.0) treatments in a factorial experimental design. Blood oxygen-carrying capacity (haemoglobin concentration, methaemoglobin concentrations and oxygen equilibrium curves), aerobic scope and functional performance traits (growth, swimming performance and post-exercise recovery) were assessed after 28 days of exposure. The oxygen-carrying capacity of fish exposed to elevated nitrate (50 and 100 mg L−1) was compromised due to reductions in haematocrit, functional haemoglobin levels and a 3-fold increase in methaemoglobin concentrations. Oxygen uptake was also impeded due to a right shift in oxygen–haemoglobin binding curves of fish exposed to nitrate and pH 4.0 simultaneously. A reduced blood oxygen-carrying capacity translated to a lowered aerobic scope, and the functional performance of fish (growth and swimming performance and increased post-exercise recovery times) was compromised by the combined effects of nitrate and low pH. These results highlight the impacts on aquatic organisms living in environments threatened by excessive nitrate and acidic pH conditions.

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