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Harter TS, Dichiera AM, Esbaugh AJ. The physiological significance of plasma-accessible carbonic anhydrase in the respiratory systems of fishes. J Comp Physiol B 2024; 194:717-737. [PMID: 38842596 DOI: 10.1007/s00360-024-01562-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 04/26/2024] [Accepted: 05/13/2024] [Indexed: 06/07/2024]
Abstract
Carbonic anhydrase (CA) activity is ubiquitously found in all vertebrate species, tissues and cellular compartments. Most species have plasma-accessible CA (paCA) isoforms at the respiratory surfaces, where the enzyme catalyzes the conversion of plasma bicarbonate to carbon dioxide (CO2) that can be excreted by diffusion. A notable exception are the teleost fishes that appear to lack paCA at their gills. The present review: (i) recapitulates the significance of CA activity and distribution in vertebrates; (ii) summarizes the current evidence for the presence or absence of paCA at the gills of fishes, from the basal cyclostomes to the derived teleosts and extremophiles such as the Antarctic icefishes; (iii) explores the contribution of paCA to organismal CO2 excretion in fishes; and (iv) the functional significance of its absence at the gills, for the specialized system of O2 transport in most teleosts; (v) outlines the multiplicity and isoform distribution of membrane-associated CAs in fishes and methodologies to determine their plasma-accessible orientation; and (vi) sketches a tentative time line for the evolutionary dynamics of branchial paCA distribution in the major groups of fishes. Finally, this review highlights current gaps in the knowledge on branchial paCA function and provides recommendations for future work.
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Affiliation(s)
- Till S Harter
- Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada.
| | - Angelina M Dichiera
- College of William and Mary, Virginia Institute of Marine Science, Gloucester Point, VA, 23062, USA
| | - Andrew J Esbaugh
- Marine Science Institute, University of Texas at Austin, Port Aransas, TX, 78373, USA
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2
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Perelló-Amorós M, Fernández-Borràs J, Yu S, Sánchez-Moya A, García de la serrana D, Gutiérrez J, Blasco J. Improving the Aerobic Capacity in Fingerlings of European Sea Bass ( Dicentrarchus labrax) through Moderate and Sustained Exercise: A Metabolic Approach. Animals (Basel) 2024; 14:274. [PMID: 38254443 PMCID: PMC10812480 DOI: 10.3390/ani14020274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 01/08/2024] [Accepted: 01/12/2024] [Indexed: 01/24/2024] Open
Abstract
Sustained swimming induces beneficial effects on growth and energy metabolism in some fish species. However, the absence of a standardized exercise regimen that guarantees an optimal response to physical activity is due to the anatomical, behavioral, and physiological differences among species, and the different conditions of tests applied, which are especially notable for the early stages of cultured species. The objective of this study was to assess the growth and metabolic responses of European sea bass submitted to continuous and moderate exercise exposure, selecting a practical swimming speed from swimming tests of groups of five fingerlings. The exercise-effects trial was carried out with 600 sea bass fingerlings (3-5 g body weight) distributed in two groups (control: voluntary swimming; exercised: under sustained swimming at 1.5 body lengths·s-1). After 6 weeks, growth parameters and proximal composition of both muscles were not altered by sustained swimming, but an increased synthetic capacity (increased RNA/DNA ratio) and more efficient use of proteins (decreased ΔN15) were observed in white muscle. The gene expression of mitochondrial proteins in white and red muscle was not affected by exercise, except for ucp3, which increased. The increase of UCP3 and Cox4 protein expression, as well as the higher COX/CS ratio of enzyme activity in white muscle, pointed out an enhanced oxidative capacity in this tissue during sustained swimming. In the protein expression of red muscle, only CS increased. All these metabolic adaptations to sustained exercise were also reflected in an enhanced maximum metabolic rate (MMR) with higher aerobic scope (AMS) of exercised fish in comparison to the non-trained fish, during a swimming test. These results demonstrated that moderate sustained swimming applied to sea bass fingerlings can improve the physical fitness of individuals through the enhancement of their aerobic capacities.
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Affiliation(s)
| | | | | | | | | | | | - Josefina Blasco
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology, University of Barcelona, Av. Diagonal 643, 08028 Barcelona, Spain; (M.P.-A.); (J.F.-B.); (S.Y.); (A.S.-M.); (D.G.d.l.s.); (J.G.)
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3
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Farrell AP. Getting to the heart of anatomical diversity and phenotypic plasticity: fish hearts are an optimal organ model in need of greater mechanistic study. J Exp Biol 2023; 226:jeb245582. [PMID: 37578108 DOI: 10.1242/jeb.245582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Natural selection has produced many vertebrate 'solutions' for the cardiac life-support system, especially among the approximately 30,000 species of fishes. For example, across species, fish have the greatest range for central arterial blood pressure and relative ventricular mass of any vertebrate group. This enormous cardiac diversity is excellent ground material for mechanistic explorations. Added to this species diversity is the emerging field of population-specific diversity, which is revealing that cardiac design and function can be tailored to a fish population's local environmental conditions. Such information is important to conservation biologists and ecologists, as well as physiologists. Furthermore, the cardiac structure and function of an individual adult fish are extremely pliable (through phenotypic plasticity), which is typically beneficial to the heart's function when environmental conditions are variable. Consequently, exploring factors that trigger cardiac remodelling with acclimation to new environments represents a marvellous opportunity for performing mechanistic studies that minimize the genetic differences that accompany cross-species comparisons. What makes the heart an especially good system for the investigation of phenotypic plasticity and species diversity is that its function can be readily evaluated at the organ level using established methodologies, unlike most other organ systems. Although the fish heart has many merits as an organ-level model to provide a mechanistic understanding of phenotypic plasticity and species diversity, bringing this potential to fruition will require productive research collaborations among physiologists, geneticists, developmental biologists and ecologists.
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Hasan MM, Ushio H, Ochiai Y. Expression and characterization of rainbow trout Oncorhynchus mykiss recombinant myoglobin. FISH PHYSIOLOGY AND BIOCHEMISTRY 2021; 47:1477-1488. [PMID: 34327612 DOI: 10.1007/s10695-021-00991-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 07/14/2021] [Indexed: 06/13/2023]
Abstract
Recombinant expression system was established for rainbow trout myoglobin (Mb) considering its unique primary structure of having one unusual deletion and two cysteine residues in contrast to the other fish Mbs. The obtained recombinant Mb without His-tag showed non-cooperative thermal denaturation profile. The presence of free cysteine residue(s) in rainbow trout Mb was demonstrated by reacting with a sulfhydryl agent, 4, 4´-dithiodipyridine, which ultimately resulted in the oxidation of Mb with characteristic changes in visible absorption spectra. Besides, the recombinant Mb displayed steady peroxidase reactivity indicating in vivo roles of Mb as a reactive oxygen species scavenger. The findings of the present study indicate that the solitary rainbow trout Mb, which ultimately manifest typical secondary structure pattern and corroborate characteristic functionality, can be over expressed in recombinant system devoid of fusion tag.
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Affiliation(s)
- Muhammad Mehedi Hasan
- Laboratory of Marine Biochemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo, 113-8657, Japan.
- Department of Fisheries Technology, Bangladesh Agricultural University, Mymensingh, 2202, Bangladesh.
| | - Hideki Ushio
- Laboratory of Marine Biochemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo, 113-8657, Japan
| | - Yoshihiro Ochiai
- Graduate School of Agriculture, Tohoku University, Aramaki, Aoba, Sendai, 980-8572, Japan
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5
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Hypoxia Performance Curve: Assess a Whole-Organism Metabolic Shift from a Maximum Aerobic Capacity towards a Glycolytic Capacity in Fish. Metabolites 2021; 11:metabo11070447. [PMID: 34357341 PMCID: PMC8307916 DOI: 10.3390/metabo11070447] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 06/29/2021] [Accepted: 07/01/2021] [Indexed: 11/16/2022] Open
Abstract
The utility of measuring whole-animal performance to frame the metabolic response to environmental hypoxia is well established. Progressively reducing ambient oxygen (O2) will initially limit maximum metabolic rate as a result of a hypoxemic state and ultimately lead to a time-limited, tolerance state supported by substrate-level phosphorylation when the O2 supply can no longer meet basic needs (standard metabolic rate, SMR). The metabolic consequences of declining ambient O2 were conceptually framed for fishes initially by Fry's hypoxic performance curve, which characterizes the hypoxemic state and its consequences to absolute aerobic scope (AAS), and Hochachka's concept of scope for hypoxic survival, which characterizes time-limited life when SMR cannot be supported by O2 supply. Yet, despite these two conceptual frameworks, the toolbox to assess whole-animal metabolic performance remains rather limited. Here, we briefly review the ongoing debate concerning the need to standardize the most commonly used assessments of respiratory performance in hypoxic fishes, namely critical O2 (the ambient O2 level below which maintenance metabolism cannot be sustained) and the incipient lethal O2 (the ambient O2 level at which a fish loses the ability to maintain upright equilibrium), and then we advance the idea that the most useful addition to the toolbox will be the limiting-O2 concentration (LOC) performance curve. Using Fry & Hart's (1948) hypoxia performance curve concept, an LOC curve was subsequently developed as an eco-physiological framework by Neil et al. and derived for a group of fish during a progressive hypoxia trial by Claireaux and Lagardère (1999). In the present review, we show how only minor modifications to available respirometry tools and techniques are needed to generate an LOC curve for individual fish. This individual approach to the LOC curve determination then increases its statistical robustness and importantly opens up the possibility of examining individual variability. Moreover, if peak aerobic performance at a given ambient O2 level of each individual is expressed as a percentage of its AAS, the water dissolved O2 that supports 50% of the individual's AAS (DOAAS-50) can be interpolated much like the P50 for an O2 hemoglobin dissociation curve (when hemoglobin is 50% saturated with O2). Thus, critical O2, incipient lethal O2, DOAAS-50 and P50 and can be directly compared within and across species. While an LOC curve for individual fish represents a start to an ongoing need to seamlessly integrate aerobic to anaerobic capacity assessments in a single, multiplexed respirometry trial, we close with a comparative exploration of some of the known whole-organism anaerobic and aerobic capacity traits to examine for correlations among them and guide the next steps.
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Esbaugh AJ, Ackerly KL, Dichiera AM, Negrete B. Is hypoxia vulnerability in fishes a by-product of maximum metabolic rate? J Exp Biol 2021; 224:269306. [PMID: 34184035 DOI: 10.1242/jeb.232520] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The metabolic index concept combines metabolic data and known thermal sensitivities to estimate the factorial aerobic scope of animals in different habitats, which is valuable for understanding the metabolic demands that constrain species' geographical distributions. An important assumption of this concept is that the O2 supply capacity (which is equivalent to the rate of oxygen consumption divided by the environmental partial pressure of oxygen: ) is constant at O2 tensions above the critical O2 threshold (i.e. the where O2 uptake can no longer meet metabolic demand). This has led to the notion that hypoxia vulnerability is not a selected trait, but a by-product of selection on maximum metabolic rate. In this Commentary, we explore whether this fundamental assumption is supported among fishes. We provide evidence that O2 supply capacity is not constant in all fishes, with some species exhibiting an elevated O2 supply capacity in hypoxic environments. We further discuss the divergent selective pressures on hypoxia- and exercise-based cardiorespiratory adaptations in fishes, while also considering the implications of a hypoxia-optimized O2 supply capacity for the metabolic index concept.
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Affiliation(s)
- Andrew J Esbaugh
- University of Texas at Austin, Marine Science Institute, Port Aransas, TX 78373, USA
| | - Kerri L Ackerly
- University of Texas at Austin, Marine Science Institute, Port Aransas, TX 78373, USA
| | - Angelina M Dichiera
- University of Texas at Austin, Marine Science Institute, Port Aransas, TX 78373, USA
| | - Benjamin Negrete
- University of Texas at Austin, Marine Science Institute, Port Aransas, TX 78373, USA
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Kraskura K, Hardison EA, Little AG, Dressler T, Prystay TS, Hendriks B, Farrell AP, Cooke SJ, Patterson DA, Hinch SG, Eliason EJ. Sex-specific differences in swimming, aerobic metabolism and recovery from exercise in adult coho salmon ( Oncorhynchus kisutch) across ecologically relevant temperatures. CONSERVATION PHYSIOLOGY 2021; 9:coab016. [PMID: 34840800 PMCID: PMC8611523 DOI: 10.1093/conphys/coab016] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 02/23/2021] [Accepted: 04/09/2021] [Indexed: 06/13/2023]
Abstract
Adult female Pacific salmon can have higher migration mortality rates than males, particularly at warm temperatures. However, the mechanisms underlying this phenomenon remain a mystery. Given the importance of swimming energetics on fitness, we measured critical swim speed, swimming metabolism, cost of transport, aerobic scope (absolute and factorial) and exercise recovery in adult female and male coho salmon (Oncorhynchus kisutch) held for 2 days at 3 environmentally relevant temperatures (9°C, 14°C, 18°C) in fresh water. Critical swimming performance (U crit) was equivalent between sexes and maximal at 14°C. Absolute aerobic scope was sex- and temperature-independent, whereas factorial aerobic scope decreased with increasing temperature in both sexes. The full cost of recovery from exhaustive exercise (excess post-exercise oxygen consumption) was higher in males compared to females. Immediately following exhaustive exercise (i.e. 1 h), recovery was impaired at 18°C for both sexes. At an intermediate time scale (i.e. 5 h), recovery in males was compromised at 14°C and 18°C compared to females. Overall, swimming, aerobic metabolism, and recovery energetics do not appear to explain the phenomenon of increased mortality rates in female coho salmon. However, our results suggest that warming temperatures compromise recovery following exhaustive exercise in both male and female salmon, which may delay migration progression and could contribute to en route mortality.
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Affiliation(s)
- K Kraskura
- Department of Ecology, Evolution and Marine Biology, University of
California, Santa Barbara, California 93106, USA
| | - E A Hardison
- Department of Ecology, Evolution and Marine Biology, University of
California, Santa Barbara, California 93106, USA
| | - A G Little
- Department of Biology Biosciences Complex, Queens
University, Kingston, Ontario K7L 3N6, Canada
| | - T Dressler
- Department of Ecology, Evolution and Marine Biology, University of
California, Santa Barbara, California 93106, USA
| | - T S Prystay
- Department of Biology and Institute of Environmental and Interdisciplinary
Science, Carleton University, Ottawa, Ontario K1S 5B6, Canada
| | - B Hendriks
- Pacific Salmon Ecology and Conservation Laboratory, Department of Forest and
Conservation Sciences, University of British Columbia, Vancouver,
British Columbia V6T 1Z4, Canada
| | - A P Farrell
- Department of Zoology, University of British
Columbia, Vancouver, British Columbia V6T 1Z4, Canada
- Faculty of Land and Food Systems, University of British
Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - S J Cooke
- Department of Biology and Institute of Environmental and Interdisciplinary
Science, Carleton University, Ottawa, Ontario K1S 5B6, Canada
| | - D A Patterson
- Fisheries and Oceans Canada, Science Branch, Pacific Region, School of Resource
and Environmental Management, Simon Fraser University, Burnaby,
British Columbia V5A 1S6, Canada
| | - S G Hinch
- Pacific Salmon Ecology and Conservation Laboratory, Department of Forest and
Conservation Sciences, University of British Columbia, Vancouver,
British Columbia V6T 1Z4, Canada
| | - E J Eliason
- Department of Ecology, Evolution and Marine Biology, University of
California, Santa Barbara, California 93106, USA
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8
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Harter TS, Brauner CJ. Teleost red blood cells actively enhance the passive diffusion of oxygen that was discovered by August Krogh. Comp Biochem Physiol A Mol Integr Physiol 2021; 253:110855. [DOI: 10.1016/j.cbpa.2020.110855] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 11/23/2020] [Accepted: 11/23/2020] [Indexed: 11/28/2022]
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Tresguerres M, Clifford AM, Harter TS, Roa JN, Thies AB, Yee DP, Brauner CJ. Evolutionary links between intra- and extracellular acid-base regulation in fish and other aquatic animals. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2020; 333:449-465. [PMID: 32458594 DOI: 10.1002/jez.2367] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 03/10/2020] [Accepted: 05/06/2020] [Indexed: 12/17/2022]
Abstract
The acid-base relevant molecules carbon dioxide (CO2 ), protons (H+ ), and bicarbonate (HCO3 - ) are substrates and end products of some of the most essential physiological functions including aerobic and anaerobic respiration, ATP hydrolysis, photosynthesis, and calcification. The structure and function of many enzymes and other macromolecules are highly sensitive to changes in pH, and thus maintaining acid-base homeostasis in the face of metabolic and environmental disturbances is essential for proper cellular function. On the other hand, CO2 , H+ , and HCO3 - have regulatory effects on various proteins and processes, both directly through allosteric modulation and indirectly through signal transduction pathways. Life in aquatic environments presents organisms with distinct acid-base challenges that are not found in terrestrial environments. These include a relatively high CO2 relative to O2 solubility that prevents internal CO2 /HCO3 - accumulation to buffer pH, a lower O2 content that may favor anaerobic metabolism, and variable environmental CO2 , pH and O2 levels that require dynamic adjustments in acid-base homeostatic mechanisms. Additionally, some aquatic animals purposely create acidic or alkaline microenvironments that drive specialized physiological functions. For example, acidifying mechanisms can enhance O2 delivery by red blood cells, lead to ammonia trapping for excretion or buoyancy purposes, or lead to CO2 accumulation to promote photosynthesis by endosymbiotic algae. On the other hand, alkalinizing mechanisms can serve to promote calcium carbonate skeletal formation. This nonexhaustive review summarizes some of the distinct acid-base homeostatic mechanisms that have evolved in aquatic organisms to meet the particular challenges of this environment.
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Affiliation(s)
- Martin Tresguerres
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, California
| | - Alexander M Clifford
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, California
| | - Till S Harter
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, California
| | - Jinae N Roa
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, California
| | - Angus B Thies
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, California
| | - Daniel P Yee
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, California
| | - Colin J Brauner
- Department of Zoology, University of British Columbia, Vancouver, Canada
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Blasco FR, Esbaugh AJ, Killen SS, Rantin FT, Taylor EW, McKenzie DJ. Using aerobic exercise to evaluate sub-lethal tolerance of acute warming in fishes. ACTA ACUST UNITED AC 2020; 223:jeb.218602. [PMID: 32381588 PMCID: PMC7225124 DOI: 10.1242/jeb.218602] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 03/01/2020] [Indexed: 01/10/2023]
Abstract
We investigated whether fatigue from sustained aerobic swimming provides a sub-lethal endpoint to define tolerance of acute warming in fishes, as an alternative to loss of equilibrium (LOE) during a critical thermal maximum (CTmax) protocol. Two species were studied, Nile tilapia (Oreochromis niloticus) and pacu (Piaractus mesopotamicus). Each fish underwent an incremental swim test to determine gait transition speed (U GT), where it first engaged the unsteady anaerobic swimming mode that preceded fatigue. After suitable recovery, each fish was exercised at 85% of their own U GT and warmed 1°C every 30 min, to identify the temperature at which they fatigued, denoted as CTswim Fish were also submitted to a standard CTmax, warming at the same rate as CTswim, under static conditions until LOE. All individuals fatigued in CTswim, at a mean temperature approximately 2°C lower than their CTmax Therefore, if exposed to acute warming in the wild, the ability to perform aerobic metabolic work would be constrained at temperatures significantly below those that directly threatened survival. The collapse in performance at CTswim was preceded by a gait transition qualitatively indistinguishable from that during the incremental swim test. This suggests that fatigue in CTswim was linked to an inability to meet the tissue oxygen demands of exercise plus warming. This is consistent with the oxygen and capacity limited thermal tolerance (OCLTT) hypothesis, regarding the mechanism underlying tolerance of warming in fishes. Overall, fatigue at CTswim provides an ecologically relevant sub-lethal threshold that is more sensitive to extreme events than LOE at CTmax.
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Affiliation(s)
- Felipe R Blasco
- Department of Physiological Sciences, Federal University of São Carlos, 13565-905 São Carlos, SP, Brazil .,Joint Graduate Program in Physiological Sciences, Federal University of São Carlos - UFSCar/São Paulo State University, UNESP Campus Araraquara, 14801-903 Araraquara, SP, Brazil
| | - Andrew J Esbaugh
- Marine Science Institute, University of Texas at Austin, Austin, TX 78373, USA
| | - Shaun S Killen
- Institute of Biodiversity, Animal Health & Comparative Medicine, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Francisco Tadeu Rantin
- Department of Physiological Sciences, Federal University of São Carlos, 13565-905 São Carlos, SP, Brazil
| | - Edwin W Taylor
- Department of Physiological Sciences, Federal University of São Carlos, 13565-905 São Carlos, SP, Brazil.,School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
| | - David J McKenzie
- Department of Physiological Sciences, Federal University of São Carlos, 13565-905 São Carlos, SP, Brazil.,MARBEC, Université de Montpellier, CNRS, Ifremer, IRD, 34000 Montpellier, France
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Mattioli CC, Takata R, de Oliveira Paes Leme F, Costa DC, Luz RK. Response of juvenile Lophiosilurus alexandri to osmotic and thermic shock. FISH PHYSIOLOGY AND BIOCHEMISTRY 2020; 46:51-61. [PMID: 31422544 DOI: 10.1007/s10695-019-00696-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 08/06/2019] [Indexed: 06/10/2023]
Abstract
The objective of the present study was to evaluate the physiological responses of juvenile Lophiosilurus alexandri submitted to osmotic and thermic shock. Thirty juveniles were used for each test, of which 10 were not subjected to stress and remained in normal conditions (fresh water at 28.0 °C). The others were submitted to stress shock (saline water of 10.0 g of salt/L or water cooled to 18.0 °C). Blood samples were taken at 0 h (no exposure to the stress factor) and 1 h and 24 h after the tests. At 24 h, the survivorship was 100% in both tests. In both the osmotic and thermic shock tests, cortisol and glucose levels were higher at 1 h but then decreased after 24 h. Lactate dehydrogenase showed differences in the temperature test, but there was no difference between 1 and 24 h after exposure to osmotic shock (P > 0.05). The difference was recorded in blood gas variables (pH, PvCO2, PvO2, hemoglobin, sO2, BE, tCO2, HCO3-, and stHCO3-) and electrolytes (Na+, Ca++, nCa++, and K+) in both experiments. With regard to hematology and blood biochemistry, exposure to thermal shock did not affect (P > 0.05) ALP, total plasma protein, hematocrit, and ALT and AST at 1 h and 24 h. ALP and total protein in the blood of fish submitted to the osmotic shock were lowest (P < 0.05) at 24 h. Leukocyte and erythrocyte counts exhibited differences after osmotic shock, in contrast to erythrocyte counts of the temperature test, which did not change in 24 h (P > 0.05). Juveniles of L. alexandri were able to reestablish the main indicators of stress (cortisol, glucose), while the others (hematological, biochemical, and gasometric) varied in compensation for normal physiological reestablishment.
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Affiliation(s)
- Cristiano Campos Mattioli
- Departamento de Zootecnia, Laboratório de Aquacultura, Universidade Federal de Minas Gerais, Avenida Antônio Carlos, no. 6627, Belo Horizonte, MG, CEP 30161-970, Brazil
| | - Rodrigo Takata
- Fundação Instituto de Pesca do Estado do Rio de Janeiro, Unidade de Pesquisa e Reprodução de Peixes, Av. Presidente Vargas, 197, Parque de Exposições, Cordeiro, RJ, CEP 28540-000, Brazil
| | - Fabiola de Oliveira Paes Leme
- Laboratório de apoio à pesquisa-LAPEQ, Universidade Federal de Minas Gerais, Avenida Antônio Carlos, no. 6627, Belo Horizonte, MG, CEP 30161-970, Brazil
| | - Deliane Cristina Costa
- Departamento de Zootecnia, Laboratório de Aquacultura, Universidade Federal de Minas Gerais, Avenida Antônio Carlos, no. 6627, Belo Horizonte, MG, CEP 30161-970, Brazil
| | - Ronald Kennedy Luz
- Departamento de Zootecnia, Laboratório de Aquacultura, Universidade Federal de Minas Gerais, Avenida Antônio Carlos, no. 6627, Belo Horizonte, MG, CEP 30161-970, Brazil.
- Laboratório de Aquacultura da Escola de Veterinária, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Belo Horizonte, MG, CEP 31270-901, Brazil.
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12
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Nudds RL, Ozolina K, Fenkes M, Wearing OH, Shiels HA. Extreme temperature combined with hypoxia, affects swimming performance in brown trout ( Salmo trutta). CONSERVATION PHYSIOLOGY 2020; 8:coz108. [PMID: 31988750 PMCID: PMC6977409 DOI: 10.1093/conphys/coz108] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 11/26/2019] [Accepted: 12/11/2019] [Indexed: 05/11/2023]
Abstract
Climate change is predicted to impact freshwater aquatic environments through changes to water temperature (T water), river flow and eutrophication. Riverine habitats contain many economically and ecologically important fishes. One such group is the migratory salmonids, which are sensitive to warm T water and low O2 (hypoxia). While several studies have investigated the independent effects of T water and hypoxia on fish physiology, the combined effects of these stressors is less well known. Furthermore, no study has investigated the effects of T water and O2 saturation levels within the range currently experienced by a salmonid species. Thus, the aim of this study was to investigate the simultaneous effects of T water and O2 saturation level on the energetics and kinematics of steady-state swimming in brown trout, Salmo trutta. No effect of O2 saturation level (70 and 100% air saturation) on tail-beat kinematics was detected. Conversely, T water (10, 14, 18 and 22°C) did affect tail-beat kinematics, but a trade-off between frequency (f tail) and amplitude (A, maximum tail excursion) maintained the Strouhal number (St = f tail• A/U, where U is swimming speed) within the theoretically most mechanically efficient range. Swimming oxygen consumption rate ([Formula: see text]) and cost of transport increased with both U and T water. The only effect of O2 saturation level was observed at the highest T water (22°C) and fastest swimming speed (two speeds were used-0.6 and 0.8 m s-1). As the extremes of this study are consistent with current summer conditions in parts of UK waterways, our findings may indicate that S. trutta will be negatively impacted by the increased T water and reduced O2 levels likely presented by anthropogenic climate change.
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Affiliation(s)
- Robert L Nudds
- Faculty of Biology, Medicine and Health, School of Biological Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, UK
- Corresponding author: Faculty of Biology, Medicine and Health, School of Biological Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
| | - Karlina Ozolina
- Faculty of Biology, Medicine and Health, School of Biological Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Miriam Fenkes
- Faculty of Biology, Medicine and Health, School of Biological Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Oliver H Wearing
- Faculty of Biology, Medicine and Health, School of Biological Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Holly A Shiels
- Faculty of Biology, Medicine and Health, School of Biological Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, UK
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Harter TS, May AG, Federspiel WJ, Supuran CT, Brauner CJ. Time course of red blood cell intracellular pH recovery following short-circuiting in relation to venous transit times in rainbow trout, Oncorhynchus mykiss. Am J Physiol Regul Integr Comp Physiol 2018; 315:R397-R407. [PMID: 29641235 DOI: 10.1152/ajpregu.00062.2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Accumulating evidence is highlighting the importance of a system of enhanced hemoglobin-oxygen (Hb-O2) unloading for cardiovascular O2 transport in teleosts. Adrenergically stimulated sodium-proton exchangers (β-NHE) create H+ gradients across the red blood cell (RBC) membrane that are short-circuited in the presence of plasma-accessible carbonic anhydrase (paCA) at the tissues; the result is a large arterial-venous pH shift that greatly enhances O2 unloading from pH-sensitive Hb. However, RBC intracellular pH (pHi) must recover during venous transit (31-90 s) to enable O2 loading at the gills. The halftimes ( t1/2) and magnitudes of RBC β-adrenergic stimulation, short-circuiting with paCA and recovery of RBC pHi, were assessed in vitro, on rainbow trout whole blood, and using changes in closed-system partial pressure of O2 as a sensitive indicator for changes in RBC pHi. In addition, the recovery rate of RBC pHi was assessed in a continuous-flow apparatus that more closely mimics RBC transit through the circulation. Results indicate that: 1) the t1/2 of β-NHE short-circuiting is likely within the residence time of blood in the capillaries, 2) the t1/2 of RBC pHi recovery is 17 s and within the time of RBC venous transit, and 3) after short-circuiting, RBCs reestablish the initial H+ gradient across the membrane and can potentially undergo repeated cycles of short-circuiting and recovery. Thus, teleosts have evolved a system that greatly enhances O2 unloading from pH-sensitive Hb at the tissues, while protecting O2 loading at the gills; the resulting increase in O2 transport per unit of blood flow may enable the tremendous athletic ability of salmonids.
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Affiliation(s)
- Till S Harter
- Department of Zoology, University of British Columbia , Vancouver, BC , Canada
| | - Alexandra G May
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.,Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - William J Federspiel
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.,Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania.,Department of Critical Care Medicine, University of Pittsburgh , Pittsburgh, Pennsylvania.,ALung Technologies, Inc. , Pittsburgh, Pennsylvania
| | - Claudiu T Supuran
- NEUROFARBA Department, Università degli Studi di Firenze , Florence , Italy
| | - Colin J Brauner
- Department of Zoology, University of British Columbia , Vancouver, BC , Canada
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Soldatov AA. The Diffusion Capacity of the Hematoparenchymal Barrier in Mammalian and Marine Fish Skeletal Muscles. J EVOL BIOCHEM PHYS+ 2018. [DOI: 10.1134/s0022093018010052] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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15
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Brauner CJ, Harter TS. Beyond just hemoglobin: Red blood cell potentiation of hemoglobin-oxygen unloading in fish. J Appl Physiol (1985) 2017; 123:935-941. [PMID: 28705992 PMCID: PMC5668442 DOI: 10.1152/japplphysiol.00114.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 06/26/2017] [Accepted: 07/09/2017] [Indexed: 11/22/2022] Open
Abstract
Teleosts comprise 95% of fish species, almost one-half of all vertebrate species, and represent one of the most successful adaptive radiation events among vertebrates. This is thought to be in part because of their unique oxygen (O2) transport system. In salmonids, recent in vitro and in vivo studies indicate that hemoglobin-oxygen (Hb-O2) unloading to tissues may be doubled or even tripled under some conditions without changes in perfusion. This is accomplished through the short circuiting of red blood cell (RBC) pH regulation, resulting in a large arterial-venous pH difference within the RBC and induced reduction in Hb-O2 affinity. This system has three prerequisites: 1) highly pH-sensitive hemoglobin, 2) rapid RBC pH regulation, and 3) a heterogeneous distribution of plasma-accessible CA in the cardiovascular system (presence in the tissues and absence at the gills). Although data are limited, these attributes may be general characteristics of teleosts. Although this system is not likely operational to the same degree in other vertebrates, some of these prerequisites do exist, and the generation and elimination of pH disequilibrium states at the RBC will likely enhance Hb-O2 unloading to some degree. In human disease states, there are conditions that may partly satisfy those for enhanced Hb-O2 unloading, tentatively an avenue for future work that may improve treatment efficacy.
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Affiliation(s)
- Colin J Brauner
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Till S Harter
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
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Harter TS, Brauner CJ. The O 2 and CO 2 Transport System in Teleosts and the Specialized Mechanisms That Enhance Hb–O 2 Unloading to Tissues. ACTA ACUST UNITED AC 2017. [DOI: 10.1016/bs.fp.2017.09.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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17
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18
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Rummer JL, Brauner CJ. Root Effect Haemoglobins in Fish May Greatly Enhance General Oxygen Delivery Relative to Other Vertebrates. PLoS One 2015; 10:e0139477. [PMID: 26436414 PMCID: PMC4593521 DOI: 10.1371/journal.pone.0139477] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 09/14/2015] [Indexed: 11/19/2022] Open
Abstract
The teleost fishes represent over half of all extant vertebrates; they occupy nearly every body of water and in doing so, occupy a diverse array of environmental conditions. We propose that their success is related to a unique oxygen (O2) transport system involving their extremely pH-sensitive haemoglobin (Hb). A reduction in pH reduces both Hb-O2 affinity (Bohr effect) and carrying capacity (Root effect). This, combined with a large arterial-venous pH change (ΔpHa-v) relative to other vertebrates, may greatly enhance tissue oxygen delivery in teleosts (e.g., rainbow trout) during stress, beyond that in mammals (e.g., human). We generated oxygen equilibrium curves (OECs) at five different CO2 tensions for rainbow trout and determined that, when Hb-O2 saturation is 50% or greater, the change in oxygen partial pressure (ΔPO2) associated with ΔpHa-v can exceed that of the mammalian Bohr effect by at least 3-fold, but as much as 21-fold. Using known ΔpHa-v and assuming a constant arterial-venous PO2 difference (Pa-vO2), Root effect Hbs can enhance O2 release to the tissues by 73.5% in trout; whereas, the Bohr effect alone is responsible for enhancing O2 release by only 1.3% in humans. Disequilibrium states are likely operational in teleosts in vivo, and therefore the ΔpHa-v, and thus enhancement of O2 delivery, could be even larger. Modeling with known Pa-vO2 in fish during exercise and hypoxia indicates that O2 release from the Hb and therefore potentially tissue O2 delivery may double during exercise and triple during some levels of hypoxia. These characteristics may be central to performance of athletic fish species such as salmonids, but may indicate that general tissue oxygen delivery may have been the incipient function of Root effect Hbs in fish, a trait strongly associated with the adaptive radiation of teleosts.
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Affiliation(s)
- Jodie L. Rummer
- Department of Zoology, University of British Columbia, 6270 University Blvd., Vancouver, BC, V6T 1Z4 Canada
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4811 Australia
- * E-mail:
| | - Colin J. Brauner
- Department of Zoology, University of British Columbia, 6270 University Blvd., Vancouver, BC, V6T 1Z4 Canada
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19
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Svendsen JC, Tirsgaard B, Cordero GA, Steffensen JF. Intraspecific variation in aerobic and anaerobic locomotion: gilthead sea bream (Sparus aurata) and Trinidadian guppy (Poecilia reticulata) do not exhibit a trade-off between maximum sustained swimming speed and minimum cost of transport. Front Physiol 2015; 6:43. [PMID: 25741285 PMCID: PMC4330683 DOI: 10.3389/fphys.2015.00043] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 01/29/2015] [Indexed: 11/17/2022] Open
Abstract
Intraspecific variation and trade-off in aerobic and anaerobic traits remain poorly understood in aquatic locomotion. Using gilthead sea bream (Sparus aurata) and Trinidadian guppy (Poecilia reticulata), both axial swimmers, this study tested four hypotheses: (1) gait transition from steady to unsteady (i.e., burst-assisted) swimming is associated with anaerobic metabolism evidenced as excess post exercise oxygen consumption (EPOC); (2) variation in swimming performance (critical swimming speed; Ucrit) correlates with metabolic scope (MS) or anaerobic capacity (i.e., maximum EPOC); (3) there is a trade-off between maximum sustained swimming speed (Usus) and minimum cost of transport (COTmin); and (4) variation in Usus correlates positively with optimum swimming speed (Uopt; i.e., the speed that minimizes energy expenditure per unit of distance traveled). Data collection involved swimming respirometry and video analysis. Results showed that anaerobic swimming costs (i.e., EPOC) increase linearly with the number of bursts in S. aurata, with each burst corresponding to 0.53 mg O2 kg−1. Data are consistent with a previous study on striped surfperch (Embiotoca lateralis), a labriform swimmer, suggesting that the metabolic cost of burst swimming is similar across various types of locomotion. There was no correlation between Ucrit and MS or anaerobic capacity in S. aurata indicating that other factors, including morphological or biomechanical traits, influenced Ucrit. We found no evidence of a trade-off between Usus and COTmin. In fact, data revealed significant negative correlations between Usus and COTmin, suggesting that individuals with high Usus also exhibit low COTmin. Finally, there were positive correlations between Usus and Uopt. Our study demonstrates the energetic importance of anaerobic metabolism during unsteady swimming, and provides intraspecific evidence that superior maximum sustained swimming speed is associated with superior swimming economy and optimum speed.
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Affiliation(s)
- Jon C Svendsen
- Molecular Eco-physiology, Interdisciplinary Center of Marine and Environmental Research, University of Porto Porto, Portugal ; Fisheries and Maritime Museum Esbjerg, Denmark
| | - Bjørn Tirsgaard
- Marine Biological Section, Biological Institute, University of Copenhagen Helsingør, Denmark
| | - Gerardo A Cordero
- Ecology, Evolution, and Organismal Biology, Iowa State University Ames, IA, USA
| | - John F Steffensen
- Marine Biological Section, Biological Institute, University of Copenhagen Helsingør, Denmark
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Randall DJ, Rummer JL, Wilson JM, Wang S, Brauner CJ. A unique mode of tissue oxygenation and the adaptive radiation of teleost fishes. ACTA ACUST UNITED AC 2015; 217:1205-14. [PMID: 24744420 DOI: 10.1242/jeb.093526] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Teleost fishes constitute 95% of extant aquatic vertebrates, and we suggest that this is related in part to their unique mode of tissue oxygenation. We propose the following sequence of events in the evolution of their oxygen delivery system. First, loss of plasma-accessible carbonic anhydrase (CA) in the gill and venous circulations slowed the Jacobs-Stewart cycle and the transfer of acid between the plasma and the red blood cells (RBCs). This ameliorated the effects of a generalised acidosis (associated with an increased capacity for burst swimming) on haemoglobin (Hb)-O2 binding. Because RBC pH was uncoupled from plasma pH, the importance of Hb as a buffer was reduced. The decrease in buffering was mediated by a reduction in the number of histidine residues on the Hb molecule and resulted in enhanced coupling of O2 and CO2 transfer through the RBCs. In the absence of plasma CA, nearly all plasma bicarbonate ultimately dehydrated to CO2 occurred via the RBCs, and chloride/bicarbonate exchange was the rate-limiting step in CO2 excretion. This pattern of CO2 excretion across the gills resulted in disequilibrium states for CO2 hydration/dehydration reactions and thus elevated arterial and venous plasma bicarbonate levels. Plasma-accessible CA embedded in arterial endothelia was retained, which eliminated the localized bicarbonate disequilibrium forming CO2 that then moved into the RBCs. Consequently, RBC pH decreased which, in conjunction with pH-sensitive Bohr/Root Hbs, elevated arterial oxygen tensions and thus enhanced tissue oxygenation. Counter-current arrangement of capillaries (retia) at the eye and later the swim bladder evolved along with the gas gland at the swim bladder. Both arrangements enhanced and magnified CO2 and acid production and, therefore, oxygen secretion to those specialised tissues. The evolution of β-adrenergically stimulated RBC Na(+)/H(+) exchange protected gill O2 uptake during stress and further augmented plasma disequilibrium states for CO2 hydration/dehydration. Finally, RBC organophosphates (e.g. NTP) could be reduced during hypoxia to further increase Hb-O2 affinity without compromising tissue O2 delivery because high-affinity Hbs could still adequately deliver O2 to the tissues via Bohr/Root shifts. We suggest that the evolution of this unique mode of tissue O2 transfer evolved in the Triassic/Jurassic Period, when O2 levels were low, ultimately giving rise to the most extensive adaptive radiation of extant vertebrates, the teleost fishes.
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Affiliation(s)
- D J Randall
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC V6T 1Z4, Canada
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21
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Jaspers RT, Testerink J, Della Gaspera B, Chanoine C, Bagowski CP, van der Laarse WJ. Increased oxidative metabolism and myoglobin expression in zebrafish muscle during chronic hypoxia. Biol Open 2014; 3:718-27. [PMID: 25063194 PMCID: PMC4133725 DOI: 10.1242/bio.20149167] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 06/17/2014] [Indexed: 11/25/2022] Open
Abstract
Fish may be extremely hypoxia resistant. We investigated how muscle fibre size and oxidative capacity in zebrafish (Danio rerio) adapt during severe chronic hypoxia. Zebrafish were kept for either 3 or 6 weeks under chronic constant hypoxia (CCH) (10% air/90%N2 saturated water). We analyzed cross-sectional area (CSA), succinate dehydrogenase (SDH) activity, capillarization, myonuclear density, myoglobin (Mb) concentration and Mb mRNA expression of high and low oxidative muscle fibres. After 3 weeks of CCH, CSA, SDH activity, Mb concentration, capillary and myonuclear density of both muscle fibre types were similar as under normoxia. In contrast, staining intensity for Mb mRNA of hypoxic high oxidative muscle fibres was 94% higher than that of normoxic controls (P<0.001). Between 3 and 6 weeks of CCH, CSA of high and low oxidative muscle fibres increased by 25 and 30%, respectively. This was similar to normoxic controls. Capillary and myonuclear density were not changed by CCH. However, in high oxidative muscle fibres of fish maintained under CCH, SDH activity, Mb concentration as well as Mb mRNA content were higher by 86%, 138% and 90%, respectively, than in muscle fibres of fish kept under normoxia (P<0.001). In low oxidative muscle fibres, SDH activity, Mb and Mb mRNA content were not significantly changed. Under normoxia, the calculated interstitial oxygen tension required to prevent anoxic cores in muscle fibres (PO2crit) of high oxidative muscle fibres was between 1.0 and 1.7 mmHg. These values were similar at 3 and 6 weeks CCH. We conclude that high oxidative skeletal muscle fibres of zebrafish continue to grow and increase oxidative capacity during CCH. Oxygen supply to mitochondria in these fibres may be facilitated by an increased Mb concentration, which is regulated by an increase in Mb mRNA content per myonucleus.
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Affiliation(s)
- Richard T Jaspers
- Laboratory for Myology, MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University Amsterdam, 1081 BT Amsterdam, The Netherlands
| | - Janwillem Testerink
- Laboratory for Myology, MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University Amsterdam, 1081 BT Amsterdam, The Netherlands Department of Integrative Zoology, Institute of Biology, Leiden University, 2333 BE Leiden, The Netherlands
| | | | | | | | - Willem J van der Laarse
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, 1007 MB Amsterdam, The Netherlands
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22
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Soldatov AA, Parfenova IA. [Stoichiometry of cytochromes and oxygen tension in skeletal muscles of marine fish]. UKRAINIAN BIOCHEMICAL JOURNAL 2014; 86:60-7. [PMID: 24868912 DOI: 10.15407/ubj86.02.060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The character of oxygen tension distribution and peculiarities of cytochromes stoichiometry in skeletal muscles of bottom and pelagic species of marine fish were compared. It is shown, that the limitation of muscle activity increases the number of hypoxic zones in the muscle tissue. The mitochondrial electron-transporting chain then obtain the uncompensated type of organization, expressed in the increase of the share of the terminal complex aa3 on the background of general reduction of cytochromes content in the muscles. The reaction is of an adaptive character and can be implemented by pelagic fish species in conditions of experimental hypokinesia.
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23
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Lefevre S, Domenici P, McKenzie DJ. Swimming in air-breathing fishes. JOURNAL OF FISH BIOLOGY 2014; 84:661-681. [PMID: 24502687 DOI: 10.1111/jfb.12308] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 11/15/2013] [Indexed: 06/03/2023]
Abstract
Fishes with bimodal respiration differ in the extent of their reliance on air breathing to support aerobic metabolism, which is reflected in their lifestyles and ecologies. Many freshwater species undertake seasonal and reproductive migrations that presumably involve sustained aerobic exercise. In the six species studied to date, aerobic exercise in swim flumes stimulated air-breathing behaviour, and there is evidence that surfacing frequency and oxygen uptake from air show an exponential increase with increasing swimming speed. In some species, this was associated with an increase in the proportion of aerobic metabolism met by aerial respiration, while in others the proportion remained relatively constant. The ecological significance of anaerobic swimming activities, such as sprinting and fast-start manoeuvres during predator-prey interactions, has been little studied in air-breathing fishes. Some species practise air breathing during recovery itself, while others prefer to increase aquatic respiration, possibly to promote branchial ion exchange to restore acid-base balance, and to remain quiescent and avoid being visible to predators. Overall, the diversity of air-breathing fishes is reflected in their swimming physiology as well, and further research is needed to increase the understanding of the differences and the mechanisms through which air breathing is controlled and used during exercise.
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Affiliation(s)
- S Lefevre
- Department of Biosciences, The Faculty of Mathematics and Natural Sciences, University of Oslo, P. O. Box 1066, 0316 Oslo, Norway
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24
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Imbrogno S. The eel heart: multilevel insights into functional organ plasticity. J Exp Biol 2013; 216:3575-86. [DOI: 10.1242/jeb.089292] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Summary
The remarkable functional homogeneity of the heart as an organ requires a well-coordinated myocardial heterogeneity. An example is represented by the selective sensitivity of the different cardiac cells to physical (i.e. shear stress and/or stretch) or chemical stimuli (e.g. catecholamines, angiotensin II, natriuretic peptides, etc.), and the cell-specific synthesis and release of these substances. The biological significance of the cardiac heterogeneity has recently received great attention in attempts to dissect the complexity of the mechanisms that control the cardiac form and function. A useful approach in this regard is to identify natural models of cardiac plasticity. Among fishes, eels (genus Anguilla), for their adaptive and acclimatory abilities, represent a group of animals so far largely used to explore the structural and ultrastructural myoarchitecture organization, as well as the complex molecular networks involved in the modulation of the heart function, such as those converting environmental signals into physiological responses. However, an overview on the existing current knowledge of eel cardiac form and function is not yet available. In this context, this review will illustrate major features of eel cardiac organization and pumping performance. Aspects of autocrine–paracrine modulation and the influence of factors such as body growth, exercise, hypoxia and temperature will highlight the power of the eel heart as an experimental model useful to decipher how the cardiac morpho-functional heterogeneities may support the uniformity of the whole-organ mechanics.
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Affiliation(s)
- Sandra Imbrogno
- Department of Biology, Ecology and Earth Sciences (BEST), University of Calabria, Italy
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25
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Eliason EJ, Clark TD, Hinch SG, Farrell AP. Cardiorespiratory performance and blood chemistry during swimming and recovery in three populations of elite swimmers: Adult sockeye salmon. Comp Biochem Physiol A Mol Integr Physiol 2013; 166:385-97. [PMID: 23880060 DOI: 10.1016/j.cbpa.2013.07.020] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Revised: 07/12/2013] [Accepted: 07/15/2013] [Indexed: 11/27/2022]
Abstract
Every year, millions of adult sockeye salmon (Oncorhynchus nerka) perform an arduous, once-in-a-lifetime migration up the Fraser River (BC, Canada) to return to their natal stream to spawn. The changes in heart rate, stroke volume, and arterio-venous oxygen extraction (i.e., factors determining rates of oxygen delivery to the tissues by the cardiovascular system) have never been directly and simultaneously measured along with whole animal oxygen uptake in a maximally swimming fish. Here, such measurements were made using three sockeye salmon populations (Early Stuart, Chilko and Quesnel), which each performed two consecutive critical swimming speed (Ucrit) challenges to provide a comprehensive quantification of cardiovascular physiology, oxygen status and blood chemistry associated with swimming and recovery. Swim performance, oxygen uptake, cardiac output, heart rate and stroke volume did not significantly vary at rest, during swimming or during recovery between populations or sexes. Despite incomplete metabolic recovery between swim challenges, all fish repeated their swim performance and similar quantitative changes in the cardiorespiratory variables were observed for each swim challenge. The high maximum cardiorespiratory performance and excellent repeat swim performance are clearly beneficial in allowing the salmon to maintain steady ground speeds and reach the distant spawning grounds in a timely manner.
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Affiliation(s)
- Erika J Eliason
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC, V6T 1Z4, Canada.
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26
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Rummer JL, McKenzie DJ, Innocenti A, Supuran CT, Brauner CJ. Root effect hemoglobin may have evolved to enhance general tissue oxygen delivery. Science 2013; 340:1327-9. [PMID: 23766325 DOI: 10.1126/science.1233692] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The Root effect is a pH-dependent reduction in hemoglobin-O2 carrying capacity. Specific to ray-finned fishes, the Root effect has been ascribed specialized roles in retinal oxygenation and swimbladder inflation. We report that when rainbow trout are exposed to elevated water carbon dioxide (CO2), red muscle partial pressure of oxygen (PO2) increases by 65%--evidence that Root hemoglobins enhance general tissue O2 delivery during acidotic stress. Inhibiting carbonic anhydrase (CA) in the plasma abolished this effect. We argue that CA activity in muscle capillaries short-circuits red blood cell (RBC) pH regulation. This acidifies RBCs, unloads O2 from hemoglobin, and elevates tissue PO2, which could double O2 delivery with no change in perfusion. This previously undescribed mechanism to enhance O2 delivery during stress may represent the incipient function of Root hemoglobins in fishes.
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Affiliation(s)
- Jodie L Rummer
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia V6T 1Z4, Canada.
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27
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Helbo S, Weber RE, Fago A. Expression patterns and adaptive functional diversity of vertebrate myoglobins. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1834:1832-9. [PMID: 23388387 DOI: 10.1016/j.bbapap.2013.01.037] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 01/23/2013] [Accepted: 01/26/2013] [Indexed: 02/06/2023]
Abstract
Recent years have witnessed a new round of research on one of the most studied proteins - myoglobin (Mb), the oxygen (O2) carrier of skeletal and heart muscle. Two major discoveries have stimulated research in this field: 1) that Mb has additional protecting functions, such as the regulation of in vivo levels of the signaling molecule nitric oxide (NO) by scavenging and generating NO during normoxia and hypoxia, respectively; and 2) that Mb in vertebrates (particularly fish) is expressed as tissue-specific isoforms in other tissues than heart and skeletal muscle, such as vessel endothelium, liver and brain, as found in cyprinid fish. Furthermore, Mb has also been found to protect against oxidative stress after hypoxia and reoxygenation and to undergo allosteric, O2-linked S-nitrosation, as in rainbow trout. Overall, the emerging evidence, particularly from fish species, indicates that Mb fulfills a broader array of physiological functions in a wider range of different tissues than hitherto appreciated. This new knowledge helps to better understand how variations in Mb structure and function may correlate with differences in animals' lifestyles and hypoxia-tolerance. This review integrates old and new results on Mb expression patterns and functional properties amongst vertebrates and discusses how these may relate to adaptive variations in different species. This article is part of a special issue entitled: Oxygen Binding and Sensing Proteins.
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Affiliation(s)
- Signe Helbo
- Department of Bioscience, Aarhus University, Denmark.
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28
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Malekinejad H, Taheri-brujerdi M, Janbaz-Acyabar H, Amniattalab A. Silymarin regulates HIF-1α and iNOS expression in the brain and gills of hypoxic-reoxygenated rainbow trout Oncorhynchus mykiss. AQUATIC BIOLOGY 2012. [DOI: 10.3354/ab00427] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Thomas JB, Gilmour KM. Low social status impairs hypoxia tolerance in rainbow trout (Oncorhynchus mykiss). J Comp Physiol B 2012; 182:651-62. [PMID: 22349625 DOI: 10.1007/s00360-012-0648-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 12/07/2011] [Accepted: 01/26/2012] [Indexed: 11/25/2022]
Abstract
In the present study, chronic behavioural stress resulting from low social status affected the physiological responses of rainbow trout (Oncorhynchus mykiss) to a subsequent acute stressor, exposure to hypoxia. Rainbow trout were confined in fork-length matched pairs for 48-72 h, and social rank was assigned based on behaviour. Dominant and subordinate fish were then exposed individually to graded hypoxia (final water PO(2), PwO(2) = 40 Torr). Catecholamine mobilization profiles differed between dominant and subordinate fish. Whereas dominant fish exhibited generally low circulating catecholamine levels until a distinct threshold for release was reached (PwO(2) = 51.5 Torr corresponding to arterial PO(2), PaO(2) = 24.1 Torr), plasma catecholamine concentrations in subordinate fish were more variable and identification of a distinct threshold for release was problematic. Among fish that mobilized catecholamines (i.e. circulating catecholamines rose above the 95% confidence interval around the baseline value), however, the circulating levels achieved in subordinate fish were significantly higher (459.9 ± 142.2 nmol L(-1), mean ± SEM, N = 12) than those in dominant fish (130.9 ± 37.9 nmol L(-1), N = 12). The differences in catecholamine mobilization occurred despite similar P(50) values in dominant (22.0 ± 1.5 Torr, N = 6) and subordinate (22.1 ± 2.2 Torr, N = 8) fish, and higher PaO(2) values in subordinate fish under severely hypoxic conditions (i.e. PwO(2) < 60 Torr). The higher PaO(2) values of subordinate fish likely reflected the greater ventilatory rates and amplitudes exhibited by these fish during severe hypoxia. At the most severe level of hypoxia, subordinate fish were unable to defend arterial blood O(2) content, which fell to approximately half (0.60 ± 0.13 mL O(2) g(-1) haemoglobin, N = 9) that of dominant fish (1.08 ± 0.09 mL O(2) g(-1) haemoglobin, N = 9). Collectively, these data indicate that chronic social stress impacts the ability of trout to respond to the additional, acute stress of hypoxia.
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Affiliation(s)
- J B Thomas
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON, K1N 6N5, Canada
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Wulff T, Jokumsen A, Højrup P, Jessen F. Time-dependent changes in protein expression in rainbow trout muscle following hypoxia. J Proteomics 2012; 75:2342-51. [PMID: 22370164 DOI: 10.1016/j.jprot.2012.02.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Revised: 01/30/2012] [Accepted: 02/02/2012] [Indexed: 12/17/2022]
Abstract
Adaptation to hypoxia is a complex process, and individual proteins will be up- or down-regulated in order to address the main challenges at any given time. To investigate the dynamics of the adaptation, rainbow trout (Oncorhynchus mykiss) was exposed to 30% of normal oxygen tension for 1, 2, 5 and 24 h respectively, after which muscle samples were taken. The successful investigation of numerous proteins in a single study was achieved by selectively separating the sarcoplasmic proteins using 2-DE. In total 46 protein spots were identified as changing in abundance in response to hypoxia using one-way ANOVA and multivariate data analysis. Proteins of interest were subsequently identified by MS/MS following tryptic digestion. The observed regulation following hypoxia in skeletal muscle was determined to be time specific, as only a limited number of proteins were regulated in response to more than one time point. The cellular response to hypoxia included regulation of proteins involved in maintaining iron homeostasis, energy levels and muscle structure. In conclusion, this proteome-based study presents a comprehensive investigation of the expression profiles of numerous proteins at four different time points. This increases our understanding of timed changes in protein expression in rainbow trout muscle following hypoxia.
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Affiliation(s)
- Tune Wulff
- National Food Institute, Technical University of Denmark, Kgs. Lyngby, Denmark.
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Oxygen dependence of metabolism and cellular adaptation in vertebrate muscles: a review. J Comp Physiol B 2011; 182:177-88. [DOI: 10.1007/s00360-011-0616-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Revised: 08/30/2011] [Accepted: 09/03/2011] [Indexed: 01/23/2023]
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Rummer JL, Brauner CJ. Plasma-accessible carbonic anhydrase at the tissue of a teleost fish may greatly enhance oxygen delivery: in vitro evidence in rainbow trout, Oncorhynchus mykiss. J Exp Biol 2011; 214:2319-28. [PMID: 21697423 DOI: 10.1242/jeb.054049] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
SUMMARY
During a generalized acidosis in rainbow trout, catecholamines are released into the blood, activating red blood cell (RBC) Na+/H+ exchange (βNHE), thus protecting RBC intracellular pH (pHi) and subsequent O2 binding at the gill. Because of the presence of a Root effect (a reduction in oxygen carrying capacity of the blood with a reduction in pH), the latter could otherwise be impaired. However, plasma-accessible carbonic anhydrase (CA) at the tissues (and absence at the gills) may result in selective short-circuiting of RBC βNHE pH regulation. This would acidify the RBCs and greatly enhance O2 delivery by exploitation of the combined Bohr-Root effect, a mechanism not previously proposed. As proof-of-principle, an in vitro closed system was developed to continuously monitor extracellular pH (pHe) and O2 tension (PO2) of rainbow trout blood. In this closed system, adding CA to acidified, adrenergically stimulated RBCs short-circuited βNHE pH regulation, resulting in an increase in PO2 by >30 mmHg, depending on the starting Hb-O2 saturation and degree of initial acidification. Interestingly, in the absence of adrenergic stimulation, addition of CA still elevated PO2, albeit to a lesser extent, a response that was absent during general NHE inhibition. If plasma-accessible CA-mediated short-circuiting is operational in vivo, the combined Bohr-Root effect system unique to teleost fishes could markedly enhance tissue O2 delivery far in excess of that in vertebrates possessing a Bohr effect alone and may lead to insights about the early evolution of the Root effect.
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Affiliation(s)
- Jodie L. Rummer
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC V6T 1Z4, Canada
| | - Colin J. Brauner
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC V6T 1Z4, Canada
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Kristensen T, Rosseland BO, Kiessling A, Djordevic B, Massabau JC. Lack of arterial PO2 downregulation in Atlantic salmon (Salmo salar L.) during long-term normoxia and hyperoxia. FISH PHYSIOLOGY AND BIOCHEMISTRY 2010; 36:1087-1095. [PMID: 20221686 DOI: 10.1007/s10695-010-9386-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Accepted: 02/22/2010] [Indexed: 05/28/2023]
Abstract
Regulation of arterial partial pressure of O2 (PaO2) in Atlantic salmon (Salmo salar) was investigated during resting conditions in normoxic and hyperoxic water. Dorsal aorta cannulated adult Atlantic salmon (1.2-1.6 kg, n=8) were exposed to 2 week sequential periods of normoxia [16.7±1.1 kPa (mean±SD)] and hyperoxia (34.1±4.9 kPa) in individual tanks containing seawater (33.7±0.2 ppt) at stable temperature conditions (8.7±0.7°C) and a light regime of L:D=12:12. Tank design and sampling procedures were optimized to provide suitable shelter and current for the fish, and to allow repeated, undisturbed sampling of blood from free-swimming fish. Fish were sampled regularly through the experimental period. PwO2, PaO2, blood ion composition (Na+, K+, Cl-), acid-base status (pH, PCO2, HCO3-), haematocrit and glucose were measured. The most frequently observed PaO2 values were in the range of 60-80% of PwO2, both during normoxia and hyperoxia, and PaO2 values were significantly lower during normoxia than during hyperoxia. Blood pH, PCO2 and HCO3- were significantly elevated during hyperoxia, while, Na+, Cl- and Hct were significantly lower. K+ and glucose showed no significant differences. This study demonstrates a lack PaO2 regulation in Atlantic salmon to low partial pressures, in contrast to previous reports for many aquatic gill breathing animals. Both during normoxia and hyperoxia, PaO2 reflects PwO2, and alterations in external PO2 consequently result in proportional arterial PO2 changes. Physiological adaptation to hyperoxia, as illustrated by changes in several blood parameters, does not include down-regulation of PaO2 in Atlantic salmon. The lack of PaO2 regulation may make Atlantic salmon vulnerable to the oxidative stress caused by increased free radical formation in hyperoxic conditions.
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Affiliation(s)
- T Kristensen
- Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, 1432, Aas, Norway.
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Helbo S, Fago A. Allosteric modulation by S-nitrosation in the low-O₂ affinity myoglobin from rainbow trout. Am J Physiol Regul Integr Comp Physiol 2010; 300:R101-8. [PMID: 20962203 DOI: 10.1152/ajpregu.00374.2010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Myoglobin (Mb) serves in the facilitated diffusion and storage of O₂ in heart and skeletal muscle, where it also regulates O₂ consumption via nitric oxide (NO) scavenging or generation. S-nitrosation at reactive cysteines may generate S-nitroso Mb (Mb-SNO) and contribute further to NO homeostasis. In being a monomer, Mb is commonly believed to lack allosteric control of heme reactivity. Here, we test whether in rainbow trout, a fast swimmer living in well-aerated water, the Mb-O₂ affinity is regulated by ionic cofactors and S-nitrosation. O₂ equilibria showed the lowest O₂ affinity ever reported among vertebrate Mbs (P₅₀ = 4.92 ± 0.29 mmHg, 25°C), a small overall heat of oxygenation (ΔH = -12.03 kcal/mol O₂), and no effect of chloride, pH, or lactate. Although the reaction with 4,4'-dithiodipyridine (4-PDS) showed 1.3-1.9 accessible thiols per heme, the reaction of Mb with S-nitroso cysteine (Cys-NO) and S-nitrosoglutathione (GSNO) to generate Mb-SNO yielded ∼0.3-0.6 and ∼0.1 SNO/heme, respectively, suggesting S-nitrosation at only one cysteine (likely Cys¹⁰). At ∼60% S-nitrosation, trout Mb-SNO showed a higher O₂ affinity (P₅₀ = 2.23 ± 0.19 mmHg, 20°C) than unmodified Mb (3.36 ± 0.11 mmHg, 20°C). Total SNO levels measured by chemiluminescence in trout myocardial preparations decreased after hypoxia, but not significantly, indicating that transnitrosation reactions between thiols may occur in vivo. Our data reveal a novel, S-nitrosation-dependent allosteric mechanism in this low-affinity Mb that may contribute to targeted O₂-linked SNO release in the hypoxic fish heart and be of importance in preserving cardiac function during intense exercise.
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Affiliation(s)
- Signe Helbo
- Department of Biological Sciences, Aarhus University, Denmark
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35
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Forgan LG, Forster ME. Oxygen-dependence of metabolic rate in the muscles of craniates. J Comp Physiol B 2010; 180:715-29. [DOI: 10.1007/s00360-010-0455-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Revised: 02/04/2010] [Accepted: 02/07/2010] [Indexed: 10/19/2022]
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36
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Janssen GJA, Jerrett AR, Black SE, Forster ME. The effects of progressive hypoxia and re-oxygenation on cardiac function, white muscle perfusion and haemoglobin saturation in anaesthetised snapper (Pagrus auratus). J Comp Physiol B 2009; 180:503-10. [PMID: 20012662 DOI: 10.1007/s00360-009-0429-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Revised: 10/28/2009] [Accepted: 11/24/2009] [Indexed: 10/20/2022]
Abstract
The effects of progressive hypoxia and re-oxygenation on cardiac function, white muscle perfusion and haemoglobin saturation were investigated in anaesthetised snapper (Pagrus auratus). White muscle perfusion and haemoglobin saturation were recorded in real time using fibre optic methodology. A marked fall in heart rate (HR) was evoked when the water bath dissolved oxygen (DO) concentration decreased below 1.5 mg L(-1). This bradycardia deepened over the subsequent 20 min of progressive hypoxia and noticeable arrhythmias occurred, suggesting that hypoxia had direct and severe effects on the cardiac myocytes. Perfusion to the white muscle decreased below a DO concentration of 3 mg L(-1), and oxyhaemoglobin concentration decreased once the DO fell below ca. 2 mg L(-1). During re-oxygenation, heart rate and white muscle perfusion increased as the DO concentration exceeded 1.9 +/- 0.1 mg L(-1), whereas haemoglobin saturation increased once the external DO concentration reached 2.9 mg L(-1). These changes occurred in anaesthetised fish, in which sensory function must be impaired, if not abolished. As white muscle perfusion both fell and increased prior to changes in white muscle oxyhaemoglobin saturation, a local hypoxia is more likely to be the consequence than the cause of the reduced blood delivery, and changes upstream from the tail vasculature must be responsible. HR and tissue haemoglobin concentrations did increase simultaneously on re-oxygenation suggesting an increased cardiac output as the cause.
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Affiliation(s)
- G J A Janssen
- Plant and Food Research Ltd, Seafood Production, PO Box 5114, Port Nelson, Nelson, New Zealand
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37
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38
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Forgan LG, Forster ME. Oxygen consumption and blood flow distribution in perfused skeletal muscle of chinook salmon. J Comp Physiol B 2008; 179:359-68. [DOI: 10.1007/s00360-008-0320-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2008] [Revised: 11/13/2008] [Accepted: 11/18/2008] [Indexed: 10/21/2022]
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Farrell AP. Cardiorespiratory performance during prolonged swimming tests with salmonids: a perspective on temperature effects and potential analytical pitfalls. Philos Trans R Soc Lond B Biol Sci 2008; 362:2017-30. [PMID: 17553773 PMCID: PMC2442863 DOI: 10.1098/rstb.2007.2111] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A prolonged swimming trial is the most common approach in studying steady-state changes in oxygen uptake, cardiac output and tissue oxygen extraction as a function of swimming speed in salmonids. The data generated by these sorts of studies are used here to support the idea that a maximum oxygen uptake is reached during a critical swimming speed test. Maximum oxygen uptake has a temperature optimum. Potential explanations are advanced to explain why maximum aerobic performance falls off at high temperature. The valuable information provided by critical swimming tests can be confounded by non-steady-state swimming behaviours, which typically occur with increasing frequency as salmonids approach fatigue. Two major concerns are noted. Foremost, measurements of oxygen uptake during swimming can considerably underestimate the true cost of transport near critical swimming speed, apparently in a temperature-dependent manner. Second, based on a comparison with voluntary swimming ascents in a raceway, forced swimming trials in a swim tunnel respirometer may underestimate critical swimming speed, possibly because fish in a swim tunnel respirometer are unable to sustain a ground speed.
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Affiliation(s)
- A P Farrell
- Zoology Department, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia, Canada V6T 1Z4.
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41
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Locomotion in Primitive Fishes. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/s1546-5098(07)26007-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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43
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Claireaux G, Couturier C, Groison AL. Effect of temperature on maximum swimming speed and cost of transport in juvenile European sea bass (Dicentrarchus labrax). ACTA ACUST UNITED AC 2006; 209:3420-8. [PMID: 16916977 DOI: 10.1242/jeb.02346] [Citation(s) in RCA: 172] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This study is an attempt to gain an integrated understanding of the interactions between temperature, locomotion activity and metabolism in the European sea bass (Dicentrarchus labrax). To our knowledge this study is among the few that have investigated the influence of the seasonal changes in water temperature on swimming performance in fish. Using a Brett-type swim-tunnel respirometer the relationship between oxygen consumption and swimming speed was determined in fish acclimatised to 7, 11, 14, 18, 22, 26 and 30 degrees C. The corresponding maximum swimming speed (U(max)), optimal swimming speed (U(opt)), active (AMR) and standard (SMR) metabolic rates as well as aerobic metabolic scope (MS) were calculated. Using simple mathematical functions, these parameters were modelled as a function of water temperature and swimming speed. Both SMR and AMR were positively related to water temperature up to 24 degrees C. Above 24 degrees C SMR and AMR levelled off and MS tended to decrease. We found a tight relationship between AMR and U(max) and observed that raising the temperature increased AMR and increased swimming ability. However, although fish swam faster at high temperature, the net cost of transport (COT(net)) at a given speed was not influence by the elevation of the water temperature. Although U(opt) doubled between 7 degrees C and 30 degrees C (from 0.3 to 0.6 m s(-1)), metabolic rate at U(opt) represented a relatively constant fraction of the animal active metabolic rate (40-45%). A proposed model integrates the effects of water temperature on the interaction between metabolism and swimming performance. In particular the controlling effect of temperature on AMR is shown to be the key factor limiting maximal swimming speed of sea bass.
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Affiliation(s)
- Guy Claireaux
- Station Méditerranéenne de l'Environnement Littoral, 1 Quai de la Daurade, Sète, 34200 France.
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Gollock MJ, Currie S, Petersen LH, Gamperl AK. Cardiovascular and haematological responses of Atlantic cod (Gadus morhua) to acute temperature increase. ACTA ACUST UNITED AC 2006; 209:2961-70. [PMID: 16857880 DOI: 10.1242/jeb.02319] [Citation(s) in RCA: 131] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
For fish to survive large acute temperature increases (i.e. >10.0 degrees C) that may bring them close to their critical thermal maximum (CTM), oxygen uptake at the gills and distribution by the cardiovascular system must increase to match tissue oxygen demand. To examine the effects of an acute temperature increase ( approximately 1.7 degrees C h(-1) to CTM) on the cardiorespiratory physiology of Atlantic cod, we (1) carried out respirometry on 10.0 degrees C acclimated fish, while simultaneously measuring in vivo cardiac parameters using Transonic probes, and (2) constructed in vitro oxygen binding curves on whole blood from 7.0 degrees C acclimated cod at a range of temperatures. Both cardiac output (Q) and heart rate (fh) increased until near the fish's CTM (22.2+/-0.2 degrees C), and then declined rapidly. Q(10) values for Q and fh were 2.48 and 2.12, respectively, and increases in both parameters were tightly correlated with O(2) consumption. The haemoglobin (Hb)-oxygen binding curve at 24.0 degrees C showed pronounced downward and rightward shifts compared to 20.0 degrees C and 7.0 degrees C, indicating that both binding capacity and affinity decreased. Further, Hb levels were lower at 24.0 degrees C than at 20.0 degrees C and 7.0 degrees C. This was likely to be due to cell swelling, as electrophoresis of Hb samples did not suggest protein denaturation, and at 24.0 degrees C Hb samples showed peak absorbance at the expected wavelength (540 nm). Our results show that cardiac function is unlikely to limit metabolic rate in Atlantic cod from Newfoundland until close to their CTM, and we suggest that decreased blood oxygen binding capacity may contribute to the plateau in oxygen consumption.
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Affiliation(s)
- M J Gollock
- Ocean Sciences Centre, Memorial University of Newfoundland, St John's, NL, A1C 5S7, Canada.
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Aniagu SO, Day N, Chipman JK, Taylor EW, Butler PJ, Winter MJ. Does exhaustive exercise result in oxidative stress and associated DNA damage in the chub (Leuciscus cephalus)? ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2006; 47:616-23. [PMID: 16878316 DOI: 10.1002/em.20247] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
DNA strand breaks [as determined by the conventional and formamidopyrimidine glycosylase (FPG)-modified Comet assay] and antioxidant defense status [as indicated by superoxide dismutase (SOD) activity and reduced glutathione (GSH) concentration] were evaluated in healthy adult chub (Leuciscus cephalus) after exhaustive exercise [swimming to their critical swimming speed (U(crit)), twice in succession with a 40 min rest period between] vs. confined (unexercised) control fish. The conventional Comet assay revealed significantly higher DNA strand breaks in all the tissues (blood, liver, and gill), with the highest increase over background evident in the epithelial gill cells of swum fish compared to the controls. Moreover, when the FPG-modified Comet assay was conducted to reveal specific oxidative lesions, the gill cells of exercised fish sustained the highest level of oxidative DNA damage in comparison to the control. Data on tissue antioxidant defense mechanism were less conclusive, with no significant differences in the tissue levels of SOD or GSH. This suggests that either the degree of oxidative stress was not great enough to evoke a response in terms of defense mechanisms or the timescale of antioxidant defense response was somewhat different from the time between the application of stress and subsequent tissue sampling. From the swimming data, U(crit) was significantly lower on the second assessment compared to the first (repeat ratio: 0.76), suggesting that the fish were exercised to a level which was not sustainable. Overall, these findings support the theory that acute extreme exercise could result in oxidative stress and associated DNA damage in fish. These observations suggest that fish living in fast flowing and polluted rivers are at increased risk of DNA damage.
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Affiliation(s)
- Stanley O Aniagu
- Molecular Pathobiology Unit, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
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