Integrative Physiological Responses to Acute Dehydration in the Rufous-Collared Sparrow: Metabolic, Enzymatic, and Oxidative Traits

Predictions indicate that birds worldwide will be affected by global warming and extreme climatic events which is especially relevant for passerines because the diurnal habits, small body size, and high mass-adjusted metabolic rates of this group make it particularly susceptible to increases in temperature and aridity. Some bird species respond to conditions that stress osmoregulation by increasing their rates of energy expenditure, nevertheless, the effect of dehydration on metabolic rates in birds has produced contrasting results. It also remains unknown whether hydration state may cause shifts in tissue-specific metabolic rates or modify tissue oxidative status. We used the rufous-collared sparrow (Zonotrichia capensis), to experimentally test the effect of dehydration on metabolic enzymes in erythrocytes, tissue oxidative status, basal metabolic rate (BMR), and total evaporative water loss. We found a significant increase in mass-adjusted BMR in water restricted (WR) birds compared to control birds (CT). Activity of cytochrome-c-oxidase (COX) in red blood cells (RBCs) was also significantly higher in the WR group relative to the CT group and this activity was positively correlated with mass-adjusted BMR. We found a moderate effect of water restriction on membrane damage of skeletal muscle. In a second set of individuals subjected to the same experimental conditions, lean mass and total water were tightly correlated and decreased by 10 and 12%, respectively, in birds in the WR group relative to the CT group. Decreases in total water and lean mass leads to an increase in mass-adjusted BMR in WR Z. capensis, suggesting that birds may simultaneously increase protein catabolism and production of metabolic water through oxidation. The significant positive relationship between BMR and COX in RBCs is a finding that requires additional research to determine whether erythrocyte metabolism is affected by dehydration per se and or it more generally reflects rates of energy expenditure in birds.

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Seasonal variation in energy expenditure, water flux and food consumption of Arabian oryx Oryx leucoryx

Journal of Experimental Biology ◽

10.1242/jeb.204.13.2301 ◽

2001 ◽

Vol 204 (13) ◽

pp. 2301-2311 ◽

Cited By ~ 4

Author(s):

Joseph B. Williams ◽

Stéphane Ostrowski ◽

Eric Bedin ◽

Khairi Ismail

Keyword(s):

Energy Expenditure ◽

Metabolic Rate ◽

Body Mass ◽

Water Loss ◽

Arid Zone ◽

Water Flux ◽

Metabolic Rates ◽

Free Living ◽

Evaporative Water ◽

Arabian Oryx

SUMMARY We report on the energy expenditure and water flux, measured in the laboratory and in the field, of the Arabian oryx Oryx leucoryx, the largest desert ruminant for which measurements of the field metabolic rate of free-living individuals have been made using doubly labeled water. Prior to extirpation of this species in the wild in 1972, conservationists sequestered a number of individuals for captive breeding; in 1989, oryx were reintroduced in Saudi Arabia into Mahazat as-Sayd (2244km2). Apart from small pools of water available after rains, oryx do not have free-standing water available for drinking and therefore rely on grasses that they eat for preformed water intake as well as their energy needs. We tested whether oryx have a reduced fasting metabolic rate and total evaporative water loss (TEWL) in the laboratory, as do some other arid-adapted mammals, and whether oryx have high field metabolic rates (FMRs) and water influx rates (WIRs), as predicted by allometric equations for large arid-zone mammals. We measured FMR and WIR during the hot summer, when plant moisture content was low and ambient temperatures were high, and after winter rains, when the water content of grasses was high. For captive oryx that weighed 84.1kg, fasting metabolic rate averaged 8980kJday−1, 16.7% lower than predictions for Artiodactyla. Our own re-analysis of minimal metabolic rates among Artiodactyla yielded the equation: logV̇O2=−0.153+0.758logM, where V̇O2 is the rate of oxygen uptake in lh−1 and M is body mass in kg. Fasting metabolic rate of oryx was only 9.1% lower than predicted, suggesting that they do not have an unusually low metabolic rate. TEWL averaged 870.0mlday−1, 63.9% lower than predicted, a remarkably low value even compared with the camel, but the mechanisms that contribute to such low rates of water loss remain unresolved. For free-living oryx, FMR was 11076kJday−1 for animals with a mean body mass of 81.5kg during summer, whereas it was 22081kJday−1 for oryx in spring with a mean body mass of 89.0kg, values that were 48.6% and 90.4% of allometric predictions, respectively. During summer, WIR averaged 1310mlH2Oday−1, whereas in spring it was 3438mlH2Oday−1. Compared with allometric predictions, WIR was 76.9% lower than expected in summer and 43.6% lower in spring. We found no evidence to support the view that the WIR of large desert ungulates is higher than that of their mesic counterparts. On the basis of the WIR of the oryx averaged over the year and the water contents of plants in their diet, we estimated that an oryx consumes 858kg of dry matter per year.

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Metabolic Rate and Energy Expenditure of the Spiny Dogfish, Squalus acanthias

Journal of the Fisheries Research Board of Canada ◽

10.1139/f78-131 ◽

1978 ◽

Vol 35 (6) ◽

pp. 816-821 ◽

Cited By ~ 54

Author(s):

J. R. Brett ◽

J. M. Blackburn

Keyword(s):

Energy Expenditure ◽

Metabolic Rate ◽

Key Words ◽

Swimming Performance ◽

Squalus Acanthias ◽

Spiny Dogfish ◽

Metabolic Rates ◽

Performance Curve ◽

Power Performance ◽

General Energy

The metabolic rate of spiny dogfish, Squalus acanthias, was determined in both a tunnel respirometer and a large, covered, circular tank (mass respirometer). Swimming performance was very poor in the respirometer, so that a power–performance curve could not be established. Instead, resting metabolic rates were determined, with higher rates induced by causing heavy thrashing (active metabolism). Routine metabolic rates were measured for the spontaneous activity characterizing behavior in the circular tank. For fish of 2 kg mean weight, the metabolic rates at 10 °C were 32.4 ± 2.6 SE (resting), 49.2 ± 5.0 SE (routine), and 88.4 ± 4.6 SE (active) mg O2∙kg−1∙h−1. Assuming that the routine rate represents a general energy expenditure in nature, this is equivalent to metabolizing about 3.8 kcal∙kg−1∙d−1 (15.9 × 103 J∙kg−1∙d−1). Key words: dogfish, metabolic rates, energetics, respiration

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Mitochondrial function in flying honeybees (Apis mellifera): respiratory chain enzymes and electron flow from complex III to oxygen

Journal of Experimental Biology ◽

10.1242/jeb.203.5.905 ◽

2000 ◽

Vol 203 (5) ◽

pp. 905-911 ◽

Cited By ~ 9

Author(s):

R.K. Suarez ◽

J.F. Staples ◽

J.R. Lighton ◽

O. Mathieu-Costello

Keyword(s):

Surface Area ◽

Muscle Mass ◽

Respiratory Chain ◽

Mitochondrial Function ◽

Electron Flow ◽

Complex Iii ◽

High Mass ◽

Metabolic Rates ◽

Turnover Rates ◽

Respiratory Enzymes

The biochemical bases for the high mass-specific metabolic rates of flying insects remain poorly understood. To gain insights into mitochondrial function during flight, metabolic rates of individual flying honeybees were measured using respirometry, and their thoracic muscles were fixed for electron microscopy. Mitochondrial volume densities and cristae surface densities, combined with biochemical data concerning cytochrome content per unit mass, were used to estimate respiratory chain enzyme densities per unit cristae surface area. Despite the high content of respiratory enzymes per unit muscle mass, these are accommodated by abundant mitochondria and high cristae surface densities such that enzyme densities per unit cristae surface area are similar to those found in mammalian muscle and liver. These results support the idea that a unit area of mitochondrial inner membrane constitutes an invariant structural unit. Rates of O(2) consumption per unit cristae surface area are much higher than those estimated in mammals as a consequence of higher enzyme turnover rates (electron transfer rates per enzyme molecule) during flight. Cytochrome c oxidase, in particular, operates close to its maximum catalytic capacity (k(cat)). Thus, high flux rates are achieved via (i) high respiratory enzyme content per unit muscle mass and (ii) the operation of these enzymes at high fractional velocities.

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Energy expenditure during load carriage at high altitude

Journal of Applied Physiology ◽

10.1152/jappl.1981.51.1.14 ◽

1981 ◽

Vol 51 (1) ◽

pp. 14-18 ◽

Cited By ~ 10

Author(s):

A. Cymerman ◽

K. B. Pandolf ◽

A. J. Young ◽

J. T. Maher

Keyword(s):

Energy Expenditure ◽

High Altitude ◽

Sea Level ◽

Prediction Equation ◽

Cycle Ergometer ◽

Load Carriage ◽

Metabolic Rates ◽

Specific Exercise ◽

Upper Limit ◽

Predicted Values

To determine the applicability of a prediction equation for energy expenditure during load carriage at high altitude that was previously validated at sea level, oxygen uptake (Vo2) was determined in five young men at 4,300 m while they walked with backpack loads of 0, 15, and 30 kg at treadmill grades of 0,8, and 16% at 1.12 m.s-1 for 10 min. Mean +/- SE maximal Vo2, determined on the cycle ergometer, was 42.2 +/- 2.3 at sea level and 35.6 +/- 1.7 ml.kg-1 .min-1 at altitude. There were no significant differences in daily Vo2 at any specific exercise intensity on days 1, 5, and 9 of exposure, nor were there any differences in endurance times at the two most difficult exercise intensities. Endurance times for 15- and 30-kg loads at 16% grade were 7.3 and 4.2 min, respectively. Measured energy expenditure was compared with that predicted by the formula of Pandolf et al. (J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 43: 577–581, 1977) and found to be significantly different. The differences could be attributed to measurements at metabolic rates exceeding 730 W or 2.1 1.min-1 Vo2. These data indicate that the prediction equation can be used at altitude for exercise intensities not exceeding this upper limit. The observed deviations from predicted values at the high exercise intensities could possibly be attributed to the occurrence of appreciable oxygen deficits and the inability to achieve steady-state conditions.

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Drivers and Consequences of Partial Migration in an Alpine Bird Species

10.32942/osf.io/9whck ◽

2021 ◽

Author(s):

Øyvind Lorvik Arnekleiv ◽

Katrine Eldegard ◽

Pål Fossland Moa ◽

Lasse Frost Eriksen ◽

Erlend B. Nilsen

Keyword(s):

Body Weight ◽

Small Body ◽

Bird Species ◽

Nesting Success ◽

Partial Migration ◽

Individual State ◽

Migratory Behaviour ◽

Willow Ptarmigan ◽

Fitness Consequences ◽

Migratory Strategy

1. Partial migration, where a portion of the population migrates between winter and summer (breeding) areas and the rest remain year-round resident, is a common phenomenon across several taxonomic groups. Yet, although several hypotheses have been put forward to explain why some individuals migrate while others stay resident – as well as the fitness consequences of the different strategies – the drivers and consequences of the decision to migrate or not are poorly understood. 2. We used data from radio-tagged female (n=73) willow ptarmigan Lagopus lagopus in an alpine study area in Central Norway to test if i) the decision to migrate was dependent on individual state variables (age and body size), ii) individuals repeated migratory behaviour between seasons, and iii) the choice of migratory strategy was related to nesting performance.3. Partially supporting our prediction that migratory strategy depends on individual state, we found that juvenile birds with small body sizes were more likely to migrate whereas large juveniles stayed resident. For adult females, we found no relationship between migratory strategy and body weight. We found strong evidence for high individual repeatability of migratory strategy between seasons. Migratory strategy did not explain variation in nesting performance among individuals, suggesting no direct influence of the chosen strategy on nesting success. 4. Our results indicate that partial migration in willow ptarmigan is determined by juvenile body weight, and that migratory behaviour becomes a part of the individual life history as a fixed strategy. Nesting success was not affected by migratory strategy in our study population, but future studies should assess other traits to further test potential fitness consequences.

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Variation in Energy Expenditure among Black‐Legged Kittiwakes: Effects of Activity‐Specific Metabolic Rates and Activity Budgets

Physiological and Biochemical Zoology ◽

10.1086/375431 ◽

2003 ◽

Vol 76 (3) ◽

pp. 375-388 ◽

Cited By ~ 34

Author(s):

P. G. R. Jodice ◽

D. D. Roby ◽

R. M. Suryan ◽

D. B. Irons ◽

A. M. Kaufman ◽

...

Keyword(s):

Energy Expenditure ◽

Metabolic Rates ◽

Activity Budgets

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Glycomacropeptide, a low-phenylalanine protein isolated from cheese whey, supports growth and attenuates metabolic stress in the murine model of phenylketonuria

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00647.2011 ◽

2012 ◽

Vol 302 (7) ◽

pp. E885-E895 ◽

Cited By ~ 30

Author(s):

Patrick Solverson ◽

Sangita G. Murali ◽

Adam S. Brinkman ◽

David W. Nelson ◽

Murray K. Clayton ◽

...

Keyword(s):

Energy Balance ◽

Food Intake ◽

Energy Expenditure ◽

Lean Mass ◽

Metabolic Stress ◽

Casein Diet ◽

Wild Type ◽

Total Fat ◽

Spleen Mass ◽

Main Effects

Phenylketonuria (PKU) is caused by a mutation in the phenylalanine (phe) hydroxylase gene and requires a low-phe diet plus amino acid (AA) formula to prevent cognitive impairment. Glycomacropeptide (GMP) contains minimal phe and provides a palatable alternative to AA formula. Our objective was to compare growth, body composition, and energy balance in Pahenu2 (PKU) and wild-type mice fed low-phe GMP, low-phe AA, or high-phe casein diets from 3–23 wk of age. The 2 × 2 × 3 design included main effects of genotype, sex, and diet. Fat and lean mass were assessed by dual-energy X-ray absorptiometry, and acute energy balance was assessed by indirect calorimetry. PKU mice showed growth and lean mass similar to wild-type littermates fed the GMP or AA diets; however, they exhibited a 3–15% increase in energy expenditure, as reflected in oxygen consumption, and a 3–30% increase in food intake. The GMP diet significantly reduced energy expenditure, food intake, and plasma phe concentration in PKU mice compared with the casein diet. The high-phe casein diet or the low-phe AA diet induced metabolic stress in PKU mice, as reflected in increased energy expenditure and intake of food and water, increased renal and spleen mass, and elevated plasma cytokine concentrations consistent with systemic inflammation. The low-phe GMP diet significantly attenuated these adverse effects. Moreover, total fat mass, %body fat, and the respiratory exchange ratio (CO2 produced/O2 consumed) were significantly lower in PKU mice fed GMP compared with AA diets. In summary, GMP provides a physiological source of low-phe dietary protein that promotes growth and attenuates the metabolic stress induced by a high-phe casein or low-phe AA diet in PKU mice.

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Survival and body composition of normal and hypothalamic obese rats in acute starvation

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1960.198.4.757 ◽

1960 ◽

Vol 198 (4) ◽

pp. 757-761 ◽

Cited By ~ 19

Author(s):

D. G. Montemurro ◽

J. A. F. Stevenson

Keyword(s):

Body Composition ◽

Metabolic Rate ◽

Fat Free Mass ◽

Prolonged Survival ◽

Metabolic Rates ◽

Total Water ◽

Fed State ◽

Normal Limits ◽

Obese Rats ◽

Acute Starvation

Female hypothalamic obese rats contained approximately 240% more fat, 10% more protein and 18% more water than did their controls, however ratio total water/fat-free mass remained within normal limits in this frank obesity. At death from starvation, the water, fat-free mass and protein compartments were significantly smaller than those of the controls, the fat compartments were not significantly different. Control rats survived starvation for 16.4 ± 1.3 days, obese rats 42.7 ± 1.8 days ( P < .001). The resting metabolic rates of normal and obese rats in the fed state were not different and both fell gradually throughout starvation. The prolonged survival of obese rats is due primarily to their excess reserve of energy and not to alterations in metabolic rate. As in the fed state, hypothalamic obese rats drank less water during starvation than did the controls. This is thought to result from direct interference with hypothalamic elements regulating thirst and the spontaneous consumption of water.

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Sugar Kelp (Saccharina latissima) Inhibits Hepatic Inflammation and Fibrosis with Increased Metabolic Rates in a Mouse Model of Diet-induced Nonalcoholic Steatohepatitis (OR24-08-19)

Current Developments in Nutrition ◽

10.1093/cdn/nzz031.or24-08-19 ◽

2019 ◽

Vol 3 (Supplement_1) ◽

Author(s):

Mi-Bo Kim ◽

Yoojin Lee ◽

Minkyung Bae ◽

Hyunju Kang ◽

Siqi Hu ◽

...

Keyword(s):

Physical Activity ◽

Liver Fibrosis ◽

Energy Expenditure ◽

Mouse Model ◽

Total Cholesterol ◽

Nonalcoholic Steatohepatitis ◽

Metabolic Rates ◽

Metabolic Disturbances ◽

Macrophage Marker ◽

M1 Macrophage

Abstract Objectives We investigated whether consumption of sugar kelp, an edible brown seaweed, can attenuate metabolic disturbances and nonalcoholic steatohepatitis (NASH) in a mouse model of NASH with evident liver fibrosis. Methods Male C57BL/6 J mice were fed a low-fat control (LF; 6% fat by wt), a high-fat/high-sucrose/high-cholesterol control (HF; 34% fat, 34% sucrose, 2.0% cholesterol by wt), or a HF containing sugar kelp (HF-Kelp; 6.0% dried sugar kelp powder by wt) for 14 weeks. Blood chemistry as well as biochemical, molecular, and histological analyses were conducted in the liver and epididymal white adipose tissue (eWAT). Metabolic rates, energy expenditure, and physical activity of mice were determined using indirect calorimetry Results Body weight of mice fed HF-Kelp was significantly lower than that of HF group. Compared to LF, HF significantly increased serum total cholesterol and glucose, which were decreased by kelp. In the liver, HF-Kelp group showed decreases in weight, triglycerides, total cholesterol, and steatosis compared with HF-fed mice. Also, kelp decreased hepatic expression of a macrophage marker F4/80 and an M1 macrophage marker CD11c. Mice fed HF-Kelp also exhibited decreased liver fibrosis as evidenced by less expression of fibrogenic genes and collagen accumulation than those of HF group. In eWAT, HF-Kelp diet reduced weight and adipocyte size compared with HF control. While HF-Kelp diet increased mRNA abundance of peroxisome proliferator activated receptor γ, it decreased the expression of collagen type VI alpha 1 chain, F4/80, CD11c, and tumor necrosis factor α, in eWAT. Oxygen consumption, carbon dioxide production, energy expenditure, and physical activity were significantly higher in HF-Kelp group than HF. Conclusions Kelp consumption markedly prevented weight gain, fat accumulation, inflammation, and fibrosis in the liver and eWAT of mice with NASH. The health benefits of kelp were accompanied by increased metabolic rates, energy expenditure, and physical activity. Therefore, kelp may be consumed to prevent obesity-associated metabolic disturbances and NASH. Funding Sources This study was supported by USDA Hatch.

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