Individual inconsistencies in basal and summit metabolic rate highlight flexibility of metabolic performance in a wintering passerine

2015 ◽  
Vol 323 (3) ◽  
pp. 179-190 ◽  
Author(s):  
Pablo Andrés Cortés ◽  
Magali Petit ◽  
Agnès Lewden ◽  
Myriam Milbergue ◽  
François Vézina
Keyword(s):  
Metabolic Rate ◽  
Metabolic Performance ◽  
Summit Metabolic Rate

scholarly journals Importance of the coronary circulation for cardiac and metabolic performance in rainbow trout ( Oncorhynchus mykiss )

2018 ◽  
Vol 14 (7) ◽  
pp. 20180063 ◽  
Author(s):  
Andreas Ekström ◽  
Michael Axelsson ◽  
Albin Gräns ◽  
Jeroen Brijs ◽  
Erik Sandblom
Keyword(s):  
Heart Rate ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Metabolic Rate ◽  
Oxygen Supply ◽  
Coronary Artery Ligation ◽  
Artery Ligation ◽  
Coronary Ligation ◽  
Metabolic Performance

Cardiac oxygenation is achieved via both coronary arterial and luminal venous oxygen supply routes in many fish species. However, the relative importance of these supplies for cardiac and aerobic metabolic performance is not fully understood. Here, we investigated how coronary artery ligation in rainbow trout ( Oncorhynchus mykiss ), implanted with heart rate loggers, affected cardiorespiratory performance in vivo . While coronary ligation significantly elevated resting heart rate, the standard metabolic rate was unchanged compared to sham-treated controls. However, coronary ligation reduced the maximum metabolic rate while heart rate remained unchanged following enforced exercise. Thus, coronary ligation reduced metabolic and heart rate scopes by 29% and 74%, respectively. Our findings highlight the importance of coronary oxygen supply for overall cardiorespiratory performance in salmonid fish, and suggest that pathological conditions that impair coronary flow (e.g. coronary arteriosclerosis) constrain the ability of fish to cope with metabolically demanding challenges such as spawning migrations and environmental warming.

Temperature regulation in the new-born lamb. V. Summit metabolism

1962 ◽  
Vol 13 (1) ◽  
pp. 100 ◽  
Author(s):  
G Alexander
Keyword(s):  
Metabolic Rate ◽  
Heat Loss ◽  
Rectal Temperature ◽  
Prolonged Exposure ◽  
High Heat ◽  
Practical Significance ◽  
Body Temperatures ◽  
Prolonged Fasting ◽  
Body Weights ◽  
Summit Metabolic Rate

"Summit metabolism" was estimated by measuring respiratory exchange during a 20 min period of falling rectal temperature. The rate of fall was controlled at about 1°C per 20 min, by varying the wind velocity while the lamb was exposed to conditions of high heat loss. At body temperatures near normal, summit metabolism was not predictable from rectal temperature. Below 36°C the metabolic rate was proportional to rectal temperature. When expressed as kilocalories per kilogram per hour, summit metabolism in young lambs was approximately constant at all body weights, and hence summit, metabolism per unit of surface area increased with increasing body weight. Heavy lambs are therefore able to maintain homeothermy under conditions of higher heat loss than light lambs. Summit metabolism was usually established at about 17 kcal kg-1 hr-1 within half an hour of birth, i.e. heat production increased rapidly to 15 times foetal levels or five times "basal" levels. There was no increase after ingestion of milk, and the summit metabolic rate appeared to decline slowly with advancing age. It also declined during prolonged exposure to cold and during prolonged fasting, particularly in very young lambs. Blood analyses indicated a great mobilization of fat and carbohydrate during exposure to conditions which evoked a summit response. The practical significance of these results is discussed.

scholarly journals Intra-Seasonal Flexibility in Avian Metabolic Performance Highlights the Uncoupling of Basal Metabolic Rate and Thermogenic Capacity

PLoS ONE ◽  
2013 ◽  
Vol 8 (6) ◽  
pp. e68292 ◽  
Author(s):  
Magali Petit ◽  
Agnès Lewden ◽  
François Vézina
Keyword(s):  
Metabolic Rate ◽  
Basal Metabolic Rate ◽  
Metabolic Performance ◽  
Thermogenic Capacity

Physiology of diving of birds and mammals

1997 ◽  
Vol 77 (3) ◽  
pp. 837-899 ◽  
Author(s):  
P. J. Butler ◽  
D. R. Jones
Keyword(s):  
Metabolic Rate ◽  
Aquatic Birds ◽  
Elephant Seals ◽  
Weddell Seals ◽  
Fur Seals ◽  
Oxygen Stores ◽  
Recent Developments ◽  
Physiological Adjustments ◽  
Low Levels ◽  
Metabolic Performance

This review concentrates on the physiological responses, and their control, in freely diving birds and mammals that enable them to remain submerged and sometimes quite active for extended periods of time. Recent developments in technology have provided much detailed information on the behavior of these fascinating animals. Unfortunately, the advances in technology have been insufficient to enable physiologists to obtain anything like the same level of detail on the metabolic rate and physiological adjustments that occur during natural diving. This has led to much speculation and calculations based on many assumptions concerning usable oxygen stores and metabolic rate during diving, in an attempt to explain the observed behavior. Despite their shortcomings, these calculations have provided useful insights into the degree of adaptations of various species of aquatic birds and mammals. Many of them, e.g., ducks, smaller penguins, fur seals, and Weddell seals, seem able to metabolize aerobically, when diving, at approximately the same (if not greater) rate as they do at the surface. Their enhanced oxygen stores are able to support aerobic metabolism, at what would not be considered unusually low levels, for the duration of the dives, although there are probably circulatory readjustments to ensure that the oxygen stores are managed judiciously. For other species, such as the larger penguins, South Georgian shag, and female elephant seals, there is a general consensus that they must either be reducing their aerobic metabolic rate when diving, possibly by way of regional hypothermia, and/or producing ATP, at least partly, by anaerobiosis and metabolizing the lactic acid when at the surface (although this is hardly likely in the case of the female elephant seals). Circulation is the proximate regulator of metabolism during aerobic diving, and heart rate is the best single indicator of circulatory adjustment. During voluntary dives, heart rates range from extreme bradycardia to well above resting, reflecting metabolic performance. Efferent cardiac control is largely parasympathetic. Reflex cardiorespiratory responses are modulated by conditioning and habituation, but reflexes predominate during extended dives and during recovery, when gas exchange is maximized.

Effects of colostrum on summit metabolic rate in Scottish Blackface lambs at five hours old

1981 ◽  
Vol 30 (3) ◽  
pp. 266-269 ◽  
Author(s):  
F.A. Bales ◽  
J. Small
Keyword(s):  
Metabolic Rate ◽  
Summit Metabolic Rate

scholarly journals Seasonal Acclimatization in the American Goldfinch Revisited: To What Extent do Metabolic Rates Vary Seasonally?

The Condor ◽  
2002 ◽  
Vol 104 (3) ◽  
pp. 548-557 ◽  
Author(s):  
Eric T. Liknes ◽  
Sarah M. Scott ◽  
David L. Swanson
Keyword(s):  
Metabolic Rate ◽  
South Dakota ◽  
Basal Metabolic Rate ◽  
Seasonal Changes ◽  
Open Circuit ◽  
Metabolic Rates ◽  
Seasonal Acclimatization ◽  
Carduelis Tristis ◽  
Para Determinar ◽  
Summit Metabolic Rate

Abstract We evaluated seasonal changes in cold tolerance, basal metabolic rate (BMR), and summit metabolic rate (Msum) for American Goldfinches (Carduelis tristis) from southeastern South Dakota to determine if goldfinches differ in pattern of metabolic acclimatization from other species of small birds. Goldfinches were captured in winter (January–February), spring (April), and summer (June–August) and tested on the day of capture. Cold exposure tests involved subjecting individual birds to a decreasing series of temperatures in an atmosphere of 79% helium to 21% oxygen (helox) concurrent with open-circuit respirometry. The helox temperature eliciting hypothermia was designated the cold limit (Tcl). Whole-animal metabolic rates were analyzed. Winter goldfinches demonstrated significantly higher BMR (46%) and Msum (31%) and significantly lower Tcl (−9.5°C vs. 1.3°C) than their summer counterparts. Spring goldfinches also showed significantly higher Msum (21%) and significantly lower Tcl (−5.3°C) than summer birds. Winter birds had higher BMR (23%) and Msum (8%) than spring birds. In winter birds, Tcl was also significantly lower than in spring birds. These data support the view that prominent winter increases in Msum and BMR are components of winter acclimatization in American Goldfinches from South Dakota and that seasonal changes in metabolism in goldfinches are similar to those for other small temperate-wintering birds. La Aclimatación Estacional en Carduelis tristis Revisitada: ¿En qué Grado Varían Estacionalmente las Tasas Metabólicas? Resumen. Evaluamos los cambios estacionales en la tolerancia al frío, la tasa metabólica basal (TMB) y la tasa metabólica pico (Mpico) en individuos de Carduelis tristis del sudeste de South Dakota para determinar si esta especie difiere de otras aves pequeñas en el patrón de aclimatación metabólica. Las aves fueron capturadas en invierno (enero–febrero), primavera (abril) y verano (junio–agosto) y sometidas a exámenes el día de captura. Los exámenes de tolerancia al frío consistieron en someter a las aves a una serie decreciente de temperaturas en una atmósfera de 79% helio y 21% oxígeno (helox) al mismo tiempo que se practicaba respirometría de circuito abierto. La temperatura que provocó hipotermia se designó como el límite de tolerancia al frío (Tfr). Se analizaron tasas metabólicas de animales completos. Las aves capturadas en el invierno presentaron TMB y Mpico significativamente mayores (46% y 31%, respectivamente) y Tfr significativamente menor (−9.5°C vs. 1.3°C) que las capturadas en el verano. Las aves de primavera también presentaron Mpico significativamente mayor (21%) y Tfr significativamente menor (−5.3°C) que las aves de verano. Las aves de invierno tuvieron mayores TMB (23%) y Mpico (8%) que las de primavera. En aves de invierno, Tfr también fue significativamente menor que en las aves de primavera. Estos datos apoyan la idea de que los incrementos invernales prominentes en Mpico y TMB son componentes de la aclimatación de invierno de C. tristis de South Dakota y que los cambios estacionales del metabolismo en esta especie son similares a los de otras aves que inviernan en la zona templada.

scholarly journals Body temperature maintenance acclimates in a winter-tenacious songbird

2020 ◽  
Author(s):  
Maria Stager ◽  
Nathan R. Senner ◽  
Bret W. Tobalske ◽  
Zachary A. Cheviron
Keyword(s):  
Body Temperature ◽  
Metabolic Rate ◽  
Heat Generation ◽  
Cold Exposure ◽  
Temperature Regulation ◽  
Thermal Conductance ◽  
Body Temperature Regulation ◽  
Ambient Conditions ◽  
Heat Conservation ◽  
Summit Metabolic Rate

ABSTRACTFlexibility in heat generation and dissipation mechanisms provides endotherms the ability to match their thermoregulatory strategy with external demands. However, the degree to which these two mechanisms account for seasonal changes in body temperature regulation is unexplored. Here we present novel data on the regulation of avian body temperature to investigate how birds alter mechanisms of heat production and heat conservation to deal with variation in ambient conditions. We subjected Dark-eyed Juncos (Junco hyemalis) to chronic cold acclimations of varying duration and subsequently quantified their metabolic rates, thermal conductance, and ability to maintain normothermia. Cold-acclimated birds adjusted traits related to both heat generation (increased summit metabolic rate) and heat conservation (decreased conductance) to improve their body temperature regulation. Increases in summit metabolic rate occurred rapidly, but plateaued after one week of cold exposure. In contrast, changes to conductance occurred only after nine weeks of cold exposure. Thus, the ability to maintain body temperature continued to improve throughout the experiment, but the mechanisms underlying this improvement changed through time. Our results demonstrate the ability of birds to adjust thermoregulatory strategies in response to thermal cues and reveal that birds may combine multiple responses to meet the specific demands of their environments.

Development of new predictive equations for basal metabolic rate in Iranian healthy adults: negligible effect of sex

2020 ◽  
pp. 1-10
Author(s):  
Bahareh Nikooyeh ◽  
Nastaran Shariatzadeh ◽  
Ali Kalayi ◽  
Maliheh Zahedirad ◽  
Tirang R. Neyestani
Keyword(s):  
Metabolic Rate ◽  
Thyroid Function ◽  
Basal Metabolic Rate ◽  
Age Groups ◽  
Thyroid Function Tests ◽  
Anthropometric Measures ◽  
Predictive Equations ◽  
Normal Thyroid Function ◽  
Asian People ◽  
Predictive Formulas

Abstract. Some studies have reported inaccuracy of predicting basal metabolic rate (BMR) by using common equations for Asian people. Thus, this study was undertaken to develop new predictive equations for the Iranian community and also to compare their accuracy with the commonly used formulas. Anthropometric measures and thyroid function were evaluated for 267 healthy subjects (18–60 y). Indirect calorimetry (InCal) was performed only for those participants with normal thyroid function tests (n = 252). Comparison of predicted RMR (both kcal/d and kcal.kg.wt−1.d−1) using current predictive formulas and measured RMR revealed that Harris-Benedict and FAO/WHO/UNU significantly over-estimated and Mifflin-St. Jeor significantly under-estimated RMR as compared to InCal measurements. In stepwise regression analysis for developing new equations, the highest r2 (=0.89) was from a model comprising sex, height and weight. However, further analyses revealed that unlike the subjects under 30 y, the association between age and the measured RMR in subjects 30 y and plus was negative (r = −0.241, p = 0.001). As a result, two separate equations were developed for these two age groups. Over 80 percent of variations were covered by the new equations. In conclusion, there were statistical significant under- and over-estimation of RMR using common predictive equations in our subjects. Using the new equations, the accuracy of the calculated RMR increased remarkably.

Sign in / Sign up

Export Citation Format

Share Document