scholarly journals Temperature and circadian effects on metabolic rate of South American echimyid rodents, Trinomys setosus and Clyomys bishopi (Rodentia: Echimyidae)

2018 ◽  
Vol 35 ◽  
pp. 1-6 ◽  
Author(s):  
Ana Paula Fabio-Braga ◽  
Wilfried Klein
Keyword(s):  
Metabolic Rate ◽  
Metabolic Activity ◽  
Respiratory Exchange Ratio ◽  
Activity Cycle ◽  
Rate Variation ◽  
South American ◽  
Metabolic Rates ◽  
Nocturnal Activity ◽  
Light Phase ◽  
Caviomorph Rodents

Basal metabolic rate (BMR) represents the lowest level of metabolic activity capable to sustain homeostasis in an endotherm and is an important tool to compare metabolic rates of different species. Echimyidae is the most specious family within caviomorph rodents, however, little is known about the biology of its species, such as Trinomys setosus (Desmarest, 1817) and Clyomys bishopi (Ávila-Pires & Wutke, 1981), a ground and an underground dwelling echimyid, respectively. The ambient temperature and circadian effects on metabolic rate were evaluated through closed-system respirometry for these two species, as well as the circadian effects on CO2 production and respiratory exchange ratio (RER). Trinomys setosus and C. bishopi showed the lowest metabolic rates (0.56 ± 0.02 mLO2.h-1.g-1 and 0.53 ± 0.03 mLO2.h-1.g-1, respectively) at 32 °C and during the light phase. Under laboratory conditions, T. setosus showed metabolic rate variation compatible with nocturnal activity, whereas C. bishopi activity cycle remains unclear. Both species showed BMR lower than expected by allometric regressions for rodents.

scholarly journals High carbohydrate diet ingestion increases post-meal lipid synthesis and drives respiratory exchange ratios above 1

2021 ◽  
Vol 224 (4) ◽  
pp. jeb240010
Author(s):  
Stav Talal ◽  
Arianne Cease ◽  
Ruth Farington ◽  
Hector E. Medina ◽  
Julio Rojas ◽  
...  
Keyword(s):  
Metabolic Rate ◽  
Respiratory Exchange Ratio ◽  
De Novo ◽  
Lipid Synthesis ◽  
South American ◽  
Hormonal Changes ◽  
Carbohydrate Diet ◽  
High Carbohydrate ◽  
Opposite Trend ◽  
The Relationship

ABSTRACTLocusts have been reported to elevate metabolic rate in response to high carbohydrate diets; this conclusion was based on metabolic rates calculated from CO2 production, a common practice for insects. However, respiratory exchange ratio (RER, CO2 production divided by O2 consumption) can rise above 1 as a result of de novo lipid synthesis, providing an alternative possible explanation of the prior findings. We studied the relationship between macronutrient ingestion, RER and lipid synthesis using South American locusts (Schistocerca cancellata) reared on artificial diets varying in protein:carbohydrate (p:c) ratio. RER increased and rose above 1 as dietary p:c ratio decreased. Lipid accumulation rates were strongly positively correlated with dietary carbohydrate content and ingestion. RERs above 1 were only observed for animals without food in the respirometry chamber, suggesting that hormonal changes after a meal may drive lipid synthesis. Schistocerca cancellata does not elevate metabolic rate on low p:c diets; in fact, the opposite trend was observed.

scholarly journals Metabolic physiology explains macroevolutionary trends in the melanic colour system across amniotes

2018 ◽  
Vol 285 (1893) ◽  
pp. 20182014 ◽  
Author(s):  
Chad M. Eliason ◽  
Julia A. Clarke
Keyword(s):  
Metabolic Rate ◽  
Expression Patterns ◽  
Specific Gene ◽  
Rate Variation ◽  
Metabolic Rates ◽  
Melanocortin System ◽  
Metabolic Physiology ◽  
Colour System ◽  
The Relationship

Metabolism links organisms to their environment through its effects on thermoregulation, feeding behaviour and energetics. Genes involved in metabolic processes have known pleiotropic effects on some melanic colour traits. Understanding links between physiology and melanic colour is critical for understanding the role of, and potential constraints on, colour production. Despite considerable variation in metabolic rates and presumed ancestral melanic coloration in vertebrates, few studies have looked at a potential relationship between these two systems in a comparative framework. Here, we test the hypothesis that changes in melanosome shape in integumentary structures track metabolic rate variation across amniotes. Using multivariate comparative analyses and incorporating both extant and fossil taxa, we find significantly faster rates of melanosome shape evolution in taxa with high metabolic rates, as well as both colour- and clade-specific differences in the relationship between metabolic rate and melanosome shape. Phylogenetic tests recover an expansion in melanosome morphospace in maniraptoran dinosaurs, as well as rate shifts within birds (in songbirds) and mammals. These findings indicate another core phenotype influenced by metabolic changes in vertebrates. They also provide a framework for testing clade-specific gene expression patterns in the melanocortin system and may improve colour reconstructions in extinct taxa.

Autoregulation of blood flow in skeletal muscle during increased metabolic activity

1962 ◽  
Vol 202 (2) ◽  
pp. 273-276 ◽  
Author(s):  
Wendell N. Stainsby
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Metabolic Rate ◽  
Metabolic Activity ◽  
Metabolic Rates ◽  
Close Link ◽  
Contracting Muscle ◽  
Resting Muscle

The effect of increased metabolic rate on autoregulation of blood flow in skeletal muscle was investigated by stimulating muscle to contract. At elevated metabolic rates good autoregulation of blood flow was observed but at higher blood flow levels than those observed in resting muscle. The degree of autoregulation in the contracting muscle was at least as great as in resting muscle. It would appear that a close link with metabolism is involved in the mechanisms associated with autoregulation of blood flow.

scholarly journals Metabolic traits in brown trout (Salmo trutta) vary in response to food restriction and intrinsic factors

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Louise C Archer ◽  
Stephen A Hutton ◽  
Luke Harman ◽  
W Russell Poole ◽  
Patrick Gargan ◽  
...  
Keyword(s):  
Life History ◽  
Metabolic Rate ◽  
Intraspecific Variation ◽  
Brown Trout ◽  
Environmental Conditions ◽  
Food Restriction ◽  
Metabolic Rates ◽  
Intrinsic Factors ◽  
Metabolic Traits ◽  
Food Conditions

Abstract Metabolic rates vary hugely within and between populations, yet we know relatively little about factors causing intraspecific variation. Since metabolic rate determines the energetic cost of life, uncovering these sources of variation is important to understand and forecast responses to environmental change. Moreover, few studies have examined factors causing intraspecific variation in metabolic flexibility. We explore how extrinsic environmental conditions and intrinsic factors contribute to variation in metabolic traits in brown trout, an iconic and polymorphic species that is threatened across much of its native range. We measured metabolic traits in offspring from two wild populations that naturally show life-history variation in migratory tactics (one anadromous, i.e. sea-migratory, one non-anadromous) that we reared under either optimal food or experimental conditions of long-term food restriction (lasting between 7 and 17 months). Both populations showed decreased standard metabolic rates (SMR—baseline energy requirements) under low food conditions. The anadromous population had higher maximum metabolic rate (MMR) than the non-anadromous population, and marginally higher SMR. The MMR difference was greater than SMR and consequently aerobic scope (AS) was higher in the anadromous population. MMR and AS were both higher in males than females. The anadromous population also had higher AS under low food compared to optimal food conditions, consistent with population-specific effects of food restriction on AS. Our results suggest different components of metabolic rate can vary in their response to environmental conditions, and according to intrinsic (population-background/sex) effects. Populations might further differ in their flexibility of metabolic traits, potentially due to intrinsic factors related to life history (e.g. migratory tactics). More comparisons of populations/individuals with divergent life histories will help to reveal this. Overall, our study suggests that incorporating an understanding of metabolic trait variation and flexibility and linking this to life history and demography will improve our ability to conserve populations experiencing global change.

scholarly journals Heat Stress Reduces Metabolic Rate While Increasing Respiratory Exchange Ratio in Growing Pigs

Animals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 215
Author(s):  
Dane W. Fausnacht ◽  
Kellie A. Kroscher ◽  
Ryan P. McMillan ◽  
Luciane S. Martello ◽  
Lance H. Baumgard ◽  
...  
Keyword(s):  
Heat Stress ◽  
Energy Expenditure ◽  
Metabolic Rate ◽  
Respiratory Exchange Ratio ◽  
Muscle Growth ◽  
Growing Pigs ◽  
Metabolic Phenotype ◽  
Substrate Regulation ◽  
Enclosed Chamber ◽  
Muscle Biopsies

Heat stress (HS) diminishes animal production, reducing muscle growth and increasing adiposity, especially in swine. Excess heat creates a metabolic phenotype with limited lipid oxidation that relies on aerobic and anaerobic glycolysis as a predominant means of energy production, potentially reducing metabolic rate. To evaluate the effects of HS on substrate utilization and energy expenditure, crossbred barrows (15.2 ± 2.4 kg) were acclimatized for 5 days (22 °C), then treated with 5 days of TN (thermal neutral, 22 °C, n = 8) or HS (35 °C, n = 8). Pigs were fed ad libitum and monitored for respiratory rate (RR) and rectal temperature. Daily energy expenditure (DEE) and respiratory exchange ratio (RER, CO2:O2) were evaluated fasted in an enclosed chamber through indirect calorimetry. Muscle biopsies were obtained from the longissimus dorsi pre/post. HS increased temperature (39.2 ± 0.1 vs. 39.6 ± 0.1 °C, p < 0.01) and RER (0.91 ± 0.02 vs. 1.02 ± 0.02 VCO2:VO2, p < 0.01), but decreased DEE/BW (68.8 ± 1.7 vs. 49.7 ± 4.8 kcal/day/kg, p < 0.01) relative to TN. Weight gain (p = 0.80) and feed intake (p = 0.84) did not differ between HS and TN groups. HS decreased muscle metabolic flexibility (~33%, p = 0.01), but increased leucine oxidation (~35%, p = 0.02) compared to baseline values. These data demonstrate that HS disrupts substrate regulation and energy expenditure in growing pigs.

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

1978 ◽  
Vol 35 (6) ◽  
pp. 816-821 ◽  
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

scholarly journals Feeding plasticity more than metabolic rate drives the productivity of economically important filter feeders in response to elevated CO2 and reduced salinity

2018 ◽  
Vol 75 (6) ◽  
pp. 2117-2128 ◽  
Author(s):  
Samuel P S Rastrick ◽  
Victoria Collier ◽  
Helen Graham ◽  
Tore Strohmeier ◽  
Nia M Whiteley ◽  
...  
Keyword(s):  
Metabolic Rate ◽  
Biological Effects ◽  
Absorption Efficiency ◽  
Environmental Stressors ◽  
Elevated Pco2 ◽  
Combined Effects ◽  
Metabolic Rates ◽  
Scope For Growth ◽  
Filter Feeders ◽  
Feeding Plasticity

Abstract Climate change driven alterations in salinity and carbonate chemistry are predicted to have significant implications particularly for northern costal organisms, including the economically important filter feeders Mytilus edulis and Ciona intestinalis. However, despite a growing number of studies investigating the biological effects of multiple environmental stressors, the combined effects of elevated pCO2 and reduced salinity remain comparatively understudied. Changes in metabolic costs associated with homeostasis and feeding/digestion in response to environmental stressors may reallocate energy from growth and reproduction, affecting performance. Although these energetic trade-offs in response to changes in routine metabolic rates have been well demonstrated fewer studies have investigated how these are affected by changes in feeding plasticity. Consequently, the present study investigated the combined effects of 26 days’ exposure to elevated pCO2 (500 µatm and 1000 µatm) and reduced salinity (30, 23, and 16) on the energy available for growth and performance (Scope for Growth) in M. edulis and C. intestinalis, and the role of metabolic rate (oxygen uptake) and feeding plasticity [clearance rate (CR) and absorption efficiency] in this process. In M. edulis exposure to elevated pCO2 resulted in a 50% reduction in Scope for Growth. However, elevated pCO2 had a much greater effect on C. intestinalis, with more than a 70% reduction in Scope for Growth. In M. edulis negative responses to elevated pCO2 are also unlikely be further affected by changes in salinity between 16 and 30. Whereas, under future predicted levels of pCO2C. intestinalis showed 100% mortality at a salinity of 16, and a &gt;90% decrease in Scope for Growth with reduced biomass at a salinity of 23. Importantly, this work demonstrates energy available for production is more dependent on feeding plasticity, i.e. the ability to regulate CR and absorption efficiency, in response to multiple stressors than on more commonly studied changes in metabolic rates.

Leptocephalus energetics: metabolism and excretion

1999 ◽  
Vol 202 (18) ◽  
pp. 2485-2493
Author(s):  
R.E. Bishop ◽  
J.J. Torres
Keyword(s):  
Metabolic Rate ◽  
Energy Budget ◽  
Citrate Synthase ◽  
Sea Water ◽  
Negative Slope ◽  
Ion Pump ◽  
Metabolic Rates ◽  
Energy Reserves ◽  
Developmental Strategy ◽  
Juvenile Form

Leptocephali are the unusual transparent larvae that are typical of eels, bonefish, tarpon and ladyfish. Unlike the larvae of all other fishes, leptocephali may remain in the plankton as larvae for several months before metamorphosing into the juvenile form. During their planktonic phase, leptocephali accumulate energy reserves in the form of glycosaminoglycans, which are then expended to fuel metamorphosis. The leptocephalus developmental strategy is thus fundamentally different from that exhibited in all other fishes in two respects: it is far longer in duration and energy reserves are accumulated. It was anticipated that the unusual character of leptocephalus development would be reflected in the energy budget of the larva. This study describes the allocation of energy to metabolism and excretion, two important elements of the energy budget. Metabolic rates were measured directly in four species of leptocephali, Paraconger caudilimbatus, Ariosoma balearicum, Gymnothorax saxicola and Ophichthus gomesii, using sealed-jar respirometry at sea. Direct measurements of metabolic rates were corroborated by measuring activities of lactate dehydrogenase and citrate synthase, two key enzymes of intermediary metabolism, in addition to that of Na(+)/K(+)-ATPase, a ubiquitous ion pump important in osmotic regulation. Excretion rates were determined by subsampling the sea water used in the respiratory incubations. The entire premetamorphic size range for each species was used in all assays. Mass-specific oxygen consumption rate, excretion rate and all enzyme activities (y) declined precipitously with increasing mass (M) according to the equation y=aM(b), where a is a species-specific constant and −1.74&lt;b&lt;-0.44. In leptocephali, the highly negative slope of the familiar allometric equation describing the relationship between mass-specific metabolic rate and mass, normally between −0.33 and 0, showed that a massive decline in metabolic rate occurs with increasing size. The result suggests that the proportion of actively metabolizing tissue also declines with size, being replaced in large measure by the metabolically inert energy depot, the glycosaminoglycans. Leptocephali can thus grow to a large size with minimal metabolic penalty, which is an unusual and successful developmental strategy.

Torpor patterns in food-deprived Myotis lucifugus (Chiroptera: Vespertilionidae) under simulated roost conditions

1991 ◽  
Vol 69 (1) ◽  
pp. 255-257 ◽  
Author(s):  
Allen Kurta
Keyword(s):  
Metabolic Rate ◽  
Myotis Lucifugus ◽  
Metabolic Rates ◽  
Laboratory Studies ◽  
Insectivorous Bats ◽  
Wet Weather ◽  
Single Night ◽  
Little Brown Bats

Temperate insectivorous bats are commonly prevented from foraging by cold or wet weather. This study examines the effect of missing a single night of foraging on the energetics of pregnant and lactating little brown bats (Myotis lucifugus) under simulated roost conditions. After not foraging, the day-roosting metabolic rate of pregnant M. lucifugus was reduced by 61% and that of lactating bats by 46%. Although previous laboratory studies predicted that food-deprived bats should remain in torpor throughout the day-roosting period, M. lucifugus consistently aroused from torpor between 11:00 and 15:00 and maintained elevated metabolic rates for the rest of the day.

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