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<b<-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.

scholarly journals Energy Partitioning in Fish: The Activityrelated Cost of Osmoregulation in a Euryhaline Cichlid

1987 ◽  
Vol 128 (1) ◽  
pp. 63-85 ◽  
Author(s):  
RICARDO FEBRY ◽  
PETER LUTZ
Keyword(s):  
Oxygen Consumption ◽  
Metabolic Rate ◽  
Swimming Speed ◽  
Sea Water ◽  
Energy Partitioning ◽  
Metabolic Rates ◽  
Total Oxygen ◽  
Total Cost ◽  
Related Cost ◽  
The Cost

We have investigated how the maintenance, net cost of swimming and total (maintenance + net cost of swimming) metabolic rates of red, hybrid tilapia (Oreochromis mossambicus ♀ × O. hornorum ♂) responded to different acclimation salinities, and if these responses correlated with changes in ion-osmoregulation (= osmoregulation) costs. Three groups of fish were acclimated to either fresh water (FW, 0‰), isosmotic sea water (ISW, 12‰) or full strength sea water (SW, 35 ‰) and oxygen consumption was measured while they swam at 10, 20, 30 and 40cms-1. Maintenance oxygen consumption (estimated by extrapolation), for an average fish (63g), increased among groups in the following order: FW < ISW < SW. The net cost of swimming increased in the order ISW < SW < FW, and total oxygen consumption (maintenance + net cost of swimming) increased in the order ISW < FW < SW. We assumed that the contribution of cardiac, branchial and swimming muscles to the net cost of swimming was proportional to swimming speed only, and therefore, at similar speeds, differences in the net cost of swimming among salinities were due to changes in the activity-related cost of osmoregulation. Consequently, the order in which the net cost of swimming increases from one group to another is the same as the order in which the cost of osmoregulation increases. Since the sequences for maintenance and total metabolic rates differed from that for the net cost of swimming, salinity-related increases in these rates cannot be attributed exclusively to changes in osmoregulation cost. We conclude, based on the differences in the net cost of swimming, that osmoregulation in FW is more expensive than in SW, and that it is cheapest in ISW. Although we were not able to estimate the total cost of osmoregulation in FW and SW, we estimated the activity-related cost, relative to the cost in ISW, at different swimming speeds (net cost of swimming in FW or SW minus net cost of swimming in ISW at each speed). For a 63-g fish in FW, this cost increased from zero at rest, to 41mgO2kg−1h−1 (16% of the total metabolic rate, 24% of the net cost swimming) at 40 cms−1. In SW the same cost increased only to 32 mgO2 kg−1h−1 (12% of the total metabolic rate, 20% of the net cost of swimming) at 40cms−1. The net cost of swimming in FW or SW increased with swimming speed at a rate 3×4 times faster

Energy metabolism during embryonic development and larval growth of an Antarctic sea urchin

1999 ◽  
Vol 202 (15) ◽  
pp. 2041-2050 ◽  
Author(s):  
A.G. Marsh ◽  
P.K. Leong ◽  
D.T. Manahan
Keyword(s):  
Metabolic Rate ◽  
Respiratory Rate ◽  
Sea Urchin ◽  
Larval Stage ◽  
Dna Content ◽  
Citrate Synthase ◽  
Larval Growth ◽  
Metabolic Rates ◽  
Cold Temperatures ◽  
Cell Numbers

Developmental energetics of an Antarctic sea urchin, Sterechinus neumayeri, were quantified to describe the physiological bases underlying ontogenetic changes in metabolic rate at extreme cold temperatures (−1.5 degrees C). Rates of development from a four-arm to a six-arm larval stage were not affected by food availability. The respiratory cost of development to the six-arm larval stage (day 60) was 14.0 mJ for fed larvae and 8.2 mJ for unfed larvae. We observed three phases of metabolic regulation during development. During embryogenesis (day 0–22), increasing metabolic rates were proportional to increases in cell numbers. During early larval development (day 22–47), the differences in respiratory rate between fed and unfed larvae were not accounted for by cell number, but by cell-specific metabolic rate (respiratory rate normalized to DNA content). Once an advanced larval stage had been reached (day 47–60), cell-specific respiratory rate and mitochondrial densities (citrate synthase activity normalized to DNA content) were more equivalent between fed and unfed larvae, suggesting that size-specific metabolic rates were determined at a level of physiological regulation that was independent of cell numbers or feeding history.

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.

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 >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.

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.

Effect of altitude on dietary-induced thermogenesis at rest and during light exercise in man

1978 ◽  
Vol 45 (3) ◽  
pp. 345-349 ◽  
Author(s):  
M. J. Stock ◽  
N. G. Norgan ◽  
A. Ferro-Luzzi ◽  
E. Evans
Keyword(s):  
Metabolic Rate ◽  
Specific Dynamic Action ◽  
Metabolic Rates ◽  
Postprandial Metabolism ◽  
Interindividual Differences ◽  
Liquid Meal ◽  
The Mean ◽  
Monte Rosa ◽  
Hypoxic Exercise ◽  
Made In

Measurements of metabolic rate and the thermic response (specific dynamic action) of a 400-kcal liquid meal were made in six subjects at rest and during light exercise. The tests were conducted before (LA1) and after (LA2) a 3-wk sojourn (HA1, HA2, HA3) at 3,650 m on the Monte Rosa. Fasting metabolic rate at rest increased inittally and then fell, as did fasting and fed exercising metabolic rates. The fall in metabolic rates, but not the initial increases, can be ascribed to the change in body weight. Resting thermic responses at altitude were only slightly lower than normal, although peak values were significantly depressed at HA2 (P less than 0.05). The mean exercising thermic response was also significantly lower at HA2 (P less than 0.05) but recovered in HA3 and LA2. In the time taken for thermic responses to decrease and recover there were interindividual differences that were best explained by the previous altitude experience of the subjects. The possibility of a cardiovascular shift during hypoxic exercise causing depression of postprandial metabolism is discussed.

scholarly journals Social Group Size and Shelter Availability Influence Individual Metabolic Traits in a Social Fish

2021 ◽  
Author(s):  
Emmanuelle Chrétien ◽  
Daniel Boisclair ◽  
Steven J Cooke ◽  
Shaun S Killen
Keyword(s):  
Metabolic Rate ◽  
Group Size ◽  
Social Group ◽  
Physiological Traits ◽  
Metabolic Rates ◽  
Night Time ◽  
The Social ◽  
Before And After ◽  
Social Treatment ◽  
Shelter Availability

Abstract Group living is widespread among animal species and yields both costs and benefits. Presence of conspecifics can restrict or enhance the expression of individual behaviour, and the recent social environment is thought to affect behavioural responses in later contexts, even when individuals are alone. However, little is known about how social group size influences the expression of individual physiological traits, including metabolic rates. There is some evidence that shoaling can reduce fish metabolic rates but this variable may be affected by habitat conditions such as shelter availability via density-dependent processes. We investigated how social group size and shelter availability influence Eurasian minnow Phoxinus phoxinus metabolic rates estimated by respirometry. Respirometry trials were conducted on fish in isolation before and after they were housed for three weeks in a social treatment consisting in a specific group size (n = 4 or 8) and shelter availability (presence or absence of plant shelter in the experimental tank). Plant shelter was placed over respirometers for half of the duration of the respirometry trials, allowing estimation of minimum day-time and night-time metabolic rates in both conditions (in the presence or absence of plant shelter). Standard metabolic rate (SMR), maximum metabolic rate (MMR), and aerobic scope (AS) were also estimated over the entire trial. Minimum day-time and night-time metabolic rates estimated while in presence of plant shelter were lower than when estimated in absence of plant shelter, both before and after individuals were housed in their social treatment. After the social treatment, SMR were higher for fish that were held in groups of four as compared to that of fish held in groups of eight while MMR showed no difference. Plant shelter availability during the social treatments did not influence SMR or MMR. Our results suggest that social group size may directly influence energy demands of individuals, highlighting the importance of understanding the role of group size on variations in physiological traits associated with energy expenditure.

scholarly journals Effects of ultraviolet radiation on metabolic rate and fitness of Aedes albopictus and Culex pipiens mosquitoes

2018 ◽  
Author(s):  
Oswaldo C Villena ◽  
Bahram Momen ◽  
Joseph Sullivan ◽  
Paul T Leisnham
Keyword(s):  
Metabolic Rate ◽  
Microbial Communities ◽  
Aedes Albopictus ◽  
Culex Pipiens ◽  
Environmental Changes ◽  
Negative Impact ◽  
Transmission Rate ◽  
Major Effect ◽  
Control Group ◽  
Metabolic Rates

Environmental changes will alter many environmental factors in the coming years including temperature, precipitation, humidity, and the amount of solar radiation reaching the earth’s surface, which in turn will have an impact on living organisms like invertebrates. In this study, we assessed the effect of UV-B radiation upon the metabolic rate and upon three fitness parameters (survival, development time, and body size) of the mosquitoes Aedes albopictus and Culex pipiens, and upon the production of microbial resources on which mosquito larvae feed in aquatic microcosms. We set up three UV-B radiation treatments mimicking levels typically measured in full-sun (FS) and shade (S) conditions, as well as a control group with no UV-B radiation (NUV). The metabolic rate expressed as heat production (µwatts/ml) for larvae and microbial community was measured at days 1, 8, and 15. Our results indicated that UV-B radiation affected the metabolic rate of both Cx. pipiens and Ae. albopictus larvae; metabolic rates were significantly higher in full-sun (FS) compared to shade (S) and no-UV condition (NUV), at days 8 and 15 compared to day 1 (Figures 1A and 1B). Culex pipiens metabolic rates were significantly higher than Ae. albopictus at day 15 compared to days 1 and 8 (Figure 1B). Metabolic rates were significantly lower in microbial communities from vials with Ae. albopictus larvae, Cx. pipiens larvae, and no larvae in FS conditions compared to vials from S and NUV conditions, especially at day 8 (Figure 2A and 2B). There was a major effect of UV-B conditions only on the survival of Ae. albopictus and Cx. pipiens mosquitoes, with significantly lower survival in FS compared to S and NUV conditions. UV-B radiation at levels found in aquatic environments in open fields showed a negative impact on the metabolic rate of Ae. albopictus and Cx. pipiens larvae and on the microbial communities on which they feed. These negative impacts could have important implications for the distribution and abundance of these mosquitoes and for the transmission rate of illness caused by the pathogens that these two broadly distributed mosquitoes transmit.

Testing the “rate of living” model: further evidence that longevity and metabolic rate are not inversely correlated in Drosophila melanogaster

2004 ◽  
Vol 97 (5) ◽  
pp. 1915-1922 ◽  
Author(s):  
Wayne A. Van Voorhies ◽  
Aziz A. Khazaeli ◽  
James W. Curtsinger
Keyword(s):  
Drosophila Melanogaster ◽  
Metabolic Rate ◽  
Recombinant Inbred ◽  
Recombinant Inbred Lines ◽  
Time Of Day ◽  
Metabolic Rates ◽  
Extended Longevity ◽  
Flow Through ◽  
The Relationship

In a recent study examining the relationship between longevity and metabolism in a large number of recombinant inbred Drosophila melanogaster lines, we found no indication of the inverse relationship between longevity and metabolic rate that one would expect under the classical “rate of living” model. A potential limitation in generalizing from that study is that it was conducted on experimental material derived from a single set of parental strains originally developed over 20 years ago. To determine whether the observations made with those lines are characteristic of the species, we studied metabolic rates and longevities in a second, independently derived set of recombinant inbred lines. We found no correlation in these lines between metabolic rate and longevity, indicating that the ability to both maintain a normal metabolic rate and have extended longevity may apply to D. melanogaster in general. To determine how closely our measurements reflect metabolic rates of flies maintained under conditions of life span assays, we used long-term, flow-through metabolic rate measurements and closed system respirometry to examine the effects of variables such as time of day, feeding state, fly density, mobility of the flies, and nitrogen knockout on D. melanogaster metabolic rate. We found that CO2 production estimated in individual flies accurately reflects metabolic rates of flies under the conditions used for longevity assays.

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