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Van Wert JC, Ekström AT, Gilbert MJH, Hendriks BJ, Cooke SJ, Patterson DA, Hinch SG, Eliason EJ. Coronary circulation enhances the aerobic performance of wild Pacific salmon. J Exp Biol 2024; 227:jeb247422. [PMID: 38841879 DOI: 10.1242/jeb.247422] [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: 01/31/2024] [Accepted: 05/24/2024] [Indexed: 06/07/2024]
Abstract
Female Pacific salmon often experience higher mortality than males during their once-in-a-lifetime up-river spawning migration, particularly when exposed to secondary stressors (e.g. high temperatures). However, the underlying mechanisms remain unknown. One hypothesis is that female Pacific salmon hearts are more oxygen-limited than those of males and are less able to supply oxygen to the body's tissues during this demanding migration. Notably, female hearts have higher coronary blood flow, which could indicate a greater reliance on this oxygen source. Oxygen limitations can develop from naturally occurring coronary blockages (i.e. coronary arteriosclerosis) found in mature salmon hearts. If female hearts rely more heavily on coronary blood flow but experience similar arteriosclerosis levels as males, they will have disproportionately impaired aerobic performance. To test this hypothesis, we measured resting (RMR) and maximum metabolic rate (MMR), aerobic scope (AS) and acute upper thermal tolerance in coho salmon (Oncorhynchus kisutch) with an intact or artificially blocked coronary oxygen supply. We also assessed venous blood oxygen and chemistry (cortisol, ions and metabolite concentrations) at different time intervals during recovery from exhaustive exercise. We found that coronary blockage impaired MMR, AS and the partial pressure of oxygen in venous blood (PvO2) during exercise recovery but did not differ between sexes. Coronary ligation lowered acute upper thermal tolerance by 1.1°C. Although we did not find evidence of enhanced female reliance on coronary supply, our findings highlight the importance of coronary blood supply for mature wild salmon, where migration success may be linked to cardiac performance, particularly during warm water conditions.
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Affiliation(s)
- Jacey C Van Wert
- Department of Ecology, Evolution & Marine Biology, University of California, Santa Barbara, CA 93106, USA
| | - Andreas T Ekström
- Department of Biological and Environmental Sciences, University of Gothenburg, 41390 Gothenburg, Sweden
| | - Matthew J H Gilbert
- Department of Zoology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Brian J Hendriks
- Pacific Salmon Ecology and Conservation Laboratory, Department of Forest and Conservation Sciences, The University of British Columbia, Vancouver, BC V6T 1Z4,Canada
| | - Steven J Cooke
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology, Carleton University, Ottawa, ON K1S 5B6, Canada
| | - David A Patterson
- Fisheries and Oceans Canada, Aquatic Research Cooperative Institute, School of Resource and Environmental Management, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Scott G Hinch
- Pacific Salmon Ecology and Conservation Laboratory, Department of Forest and Conservation Sciences, The University of British Columbia, Vancouver, BC V6T 1Z4,Canada
| | - Erika J Eliason
- Department of Ecology, Evolution & Marine Biology, University of California, Santa Barbara, CA 93106, USA
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2
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Zena LA, Ekström AT, Morgenroth D, McArley T, Axelsson M, Sundh H, Palmquist A, Johansen IB, Gräns A, Sandblom E. Beating the heart failure odds: long-term survival after myocardial ischemia in juvenile rainbow trout. Am J Physiol Regul Integr Comp Physiol 2024; 326:R484-R498. [PMID: 38406842 DOI: 10.1152/ajpregu.00005.2024] [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: 01/08/2024] [Revised: 02/20/2024] [Accepted: 02/21/2024] [Indexed: 02/27/2024]
Abstract
Salmonid fish include some of the most valued cultured fish species worldwide. Unlike most other fish, the hearts of salmonids, including Atlantic salmon and rainbow trout, have a well-developed coronary circulation. Consequently, their hearts' reliance on oxygenation through coronary arteries leaves them prone to coronary lesions, believed to precipitate myocardial ischemia. Here, we mimicked such coronary lesions by subjecting groups of juvenile rainbow trout to coronary ligation, assessing histomorphological myocardial changes associated with ischemia and scarring in the context of cardiac arrhythmias using electrocardiography (ECG). Notable ECG changes resembling myocardial ischemia-like ECG in humans, such as atrioventricular blocks and abnormal ventricular depolarization (prolonged and fragmented QRS complex), as well as repolarization (long QT interval) patterns, were observed during the acute phase of myocardial ischemia. A remarkable 100% survival rate was observed among juvenile trout subjected to coronary ligation after 24 wk. Recovery from coronary ligation occurred through adaptive ventricular remodeling, coupled with a fast cardiac revascularization response. These findings carry significant implications for understanding the mechanisms governing cardiac health in salmonid fish, a family particularly susceptible to cardiac diseases. Furthermore, our results provide valuable insights into comparative studies on the evolution, pathophysiology, and ontogeny of vertebrate cardiac repair and restoration.NEW & NOTEWORTHY Juvenile rainbow trout exhibit a remarkable capacity to recover from cardiac injury caused by myocardial ischemia. Recovery from cardiac damage occurs through adaptive ventricular remodeling, coupled with a rapid cardiac revascularization response. These findings carry significant implications for understanding the mechanisms governing cardiac health within salmonid fishes, which are particularly susceptible to cardiac diseases.
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Affiliation(s)
- Lucas A Zena
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
- Department of Applied Animal Science and Welfare, Swedish University of Agricultural Sciences, Gothenburg, Sweden
| | - Andreas T Ekström
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Daniel Morgenroth
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Tristan McArley
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Michael Axelsson
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Henrik Sundh
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Anders Palmquist
- Department of Biomaterials, University of Gothenburg, Gothenburg, Sweden
| | - Ida B Johansen
- Department of Preclinical Sciences and Pathology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
| | - Albin Gräns
- Department of Applied Animal Science and Welfare, Swedish University of Agricultural Sciences, Gothenburg, Sweden
| | - Erik Sandblom
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
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3
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Ekström A, Hendriks B, Van Wert JC, Gilbert MJH, Farrell AP, Cooke SJ, Patterson DA, Hinch SG, Eliason EJ. Impairing cardiac oxygen supply in swimming coho salmon compromises their heart function and tolerance to acute warming. Sci Rep 2023; 13:21204. [PMID: 38040741 PMCID: PMC10692232 DOI: 10.1038/s41598-023-47713-5] [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: 05/08/2023] [Accepted: 11/17/2023] [Indexed: 12/03/2023] Open
Abstract
Climatic warming elevates mortality for many salmonid populations during their physically challenging up-river spawning migrations, yet, the mechanisms underlying the increased mortality remain elusive. One hypothesis posits that a cardiac oxygen insufficiency impairs the heart's capacity to pump sufficient oxygen to body tissues to sustain up-river swimming, especially in warm water when oxygen availability declines and cardiac and whole-animal oxygen demand increases. We tested this hypothesis by measuring cardiac and metabolic (cardiorespiratory) performance, and assessing the upper thermal tolerance of coho salmon (Oncorhynchus kisutch) during sustained swimming and acute warming. By surgically ligating the coronary artery, which naturally accumulates arteriosclerotic lesions in migrating salmon, we partially impaired oxygen supply to the heart. Coronary ligation caused drastic cardiac impairment during swimming, even at benign temperatures, and substantially constrained cardiorespiratory performance during swimming and progressive warming compared to sham-operated control fish. Furthermore, upper thermal tolerance during swimming was markedly reduced (by 4.4 °C) following ligation. While the cardiorespiratory capacity of female salmon was generally lower at higher temperatures compared to males, upper thermal tolerance during swimming was similar between sexes within treatment groups. Cardiac oxygen supply is a crucial determinant for the migratory capacity of salmon facing climatic environmental warming.
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Affiliation(s)
- Andreas Ekström
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, 40530, Gothenburg, Sweden.
| | - Brian Hendriks
- Pacific Salmon Ecology and Conservation Laboratory, Department of Forest and Conservation Sciences, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Jacey C Van Wert
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA, 93106-9620, USA
| | - Matthew J H Gilbert
- Department of Zoology, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Anthony P Farrell
- Department of Zoology, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Steven J Cooke
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology, Carleton University, Ottawa, ON, K1S 5B6, Canada
| | - David A Patterson
- Fisheries and Oceans Canada, Cooperative Resource Management Institute, School of Resource and Environmental Management, Simon Fraser University, Burnaby, BC, V5A 1S6, Canada
| | - Scott G Hinch
- Pacific Salmon Ecology and Conservation Laboratory, Department of Forest and Conservation Sciences, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Erika J Eliason
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA, 93106-9620, USA
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4
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Wallbom N, Zena LA, McArley TJ, Ekström A, Axelsson M, Gräns A, Sandblom E, Morgenroth D, Kallstenius N. Increased reliance on coronary perfusion for cardiorespiratory performance in seawater-acclimated rainbow trout. J Exp Biol 2023; 226:286759. [PMID: 36700410 PMCID: PMC10088527 DOI: 10.1242/jeb.244733] [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: 06/28/2022] [Accepted: 01/09/2023] [Indexed: 01/27/2023]
Abstract
Salmonid ventricles are composed of spongy and compact myocardium, the latter being perfused via a coronary circulation. Rainbow trout (Oncorhynchus mykiss) acclimated to sea water have higher proportions of compact myocardium and display stroke volume-mediated elevations in resting cardiac output relative to freshwater-acclimated trout, probably to meet the higher metabolic needs of osmoregulatory functions. Here, we tested the hypothesis that cardiorespiratory performance of rainbow trout in sea water is more dependent on coronary perfusion by assessing the effects of coronary ligation on cardiorespiratory function in resting and exhaustively exercised trout acclimated to fresh water or sea water. While ligation only had minor effects on resting cardiorespiratory function across salinities, cardiac function after chasing to exhaustion was impaired, presumably as a consequence of atrioventricular block. Ligation reduced maximum O2 consumption rate by 33% and 17% in fish acclimated to sea water and fresh water, respectively, which caused corresponding 41% and 17% reductions in aerobic scope. This was partly explained by different effects on cardiac performance, as maximum stroke volume was only significantly impaired by ligation in sea water, resulting in 38% lower maximum cardiac output in seawater compared with 28% in fresh water. The more pronounced effect on respiratory performance in sea water was presumably also explained by lower blood O2 carrying capacity, with ligated seawater-acclimated trout having 16% and 17% lower haemoglobin concentration and haematocrit, respectively, relative to ligated freshwater trout. In conclusion, we show that the coronary circulation allows seawater-acclimated trout to maintain aerobic scope at a level comparable to that in fresh water.
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Affiliation(s)
- Nicklas Wallbom
- Department of Biological and Environmental Sciences, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Lucas A Zena
- Department of Biological and Environmental Sciences, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Tristan J McArley
- Department of Biological and Environmental Sciences, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Andreas Ekström
- Department of Biological and Environmental Sciences, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Michael Axelsson
- Department of Biological and Environmental Sciences, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Albin Gräns
- Department of Animal Environment and Health, Swedish University of Agricultural Sciences, 405 30 Gothenburg, Sweden
| | - Erik Sandblom
- Department of Biological and Environmental Sciences, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Daniel Morgenroth
- Department of Biological and Environmental Sciences, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Nicklas Kallstenius
- University of Gothenburg, Department of Biological and Environmental Sciences, Sweden
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5
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O’Brien KM, Oldham CA, Sarrimanolis J, Fish A, Castellini L, Vance J, Lekanof H, Crockett EL. Warm acclimation alters antioxidant defences but not metabolic capacities in the Antarctic fish, Notothenia coriiceps. CONSERVATION PHYSIOLOGY 2022; 10:coac054. [PMID: 35935168 PMCID: PMC9346567 DOI: 10.1093/conphys/coac054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 06/14/2022] [Accepted: 07/19/2022] [Indexed: 06/15/2023]
Abstract
The Southern Ocean surrounding the Western Antarctic Peninsula region is rapidly warming. Survival of members of the dominant suborder of Antarctic fishes, the Notothenioidei, will likely require thermal plasticity and adaptive capacity in key traits delimiting thermal tolerance. Herein, we have assessed the thermal plasticity of several cellular and biochemical pathways, many of which are known to be associated with thermal tolerance in notothenioids, including mitochondrial function, activities of aerobic and anaerobic enzymes, antioxidant defences, protein ubiquitination and degradation in cardiac, oxidative skeletal muscles and gill of Notothenia coriiceps warm acclimated to 4°C for 22 days or 5°C for 42 days. Levels of triacylglycerol (TAG) were measured in liver and oxidative and glycolytic skeletal muscles, and glycogen in liver and glycolytic muscle to assess changes in energy stores. Metabolic pathways displayed minimal thermal plasticity, yet antioxidant defences were lower in heart and oxidative skeletal muscles of warm-acclimated animals compared with animals held at ambient temperature. Despite higher metabolic rates at elevated temperature, energy storage depots of TAG and glycogen increase in liver and remain unchanged in muscle with warm acclimation. Overall, our studies reveal that N. coriiceps displays thermal plasticity in some key traits that may contribute to their survival as the Southern Ocean continues to warm.
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Affiliation(s)
- Kristin M O’Brien
- Institute of Arctic Biology, University of Alaska, Fairbanks, AK 99775 USA
| | - Corey A Oldham
- Institute of Arctic Biology, University of Alaska, Fairbanks, AK 99775 USA
| | - Jon Sarrimanolis
- Institute of Arctic Biology, University of Alaska, Fairbanks, AK 99775 USA
| | - Autumn Fish
- Institute of Arctic Biology, University of Alaska, Fairbanks, AK 99775 USA
| | - Luke Castellini
- Institute of Arctic Biology, University of Alaska, Fairbanks, AK 99775 USA
| | - Jenna Vance
- Department of Biological Sciences, Ohio University, Athens, OH 45701 USA
| | - Hayley Lekanof
- Institute of Arctic Biology, University of Alaska, Fairbanks, AK 99775 USA
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6
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Muir CA, Garner SR, Damjanovski S, Neff BD. Temperature-dependent plasticity mediates heart morphology and thermal performance of cardiac function in juvenile Atlantic salmon (Salmo salar). J Exp Biol 2022; 225:276049. [PMID: 35860948 DOI: 10.1242/jeb.244305] [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: 05/17/2022] [Accepted: 07/08/2022] [Indexed: 11/20/2022]
Abstract
In many fishes, upper thermal tolerance is thought to be limited in part by the heart's ability to meet increased oxygen demands during periods of high temperature. Temperature-dependent plasticity within the cardiovascular system may help fishes cope with the thermal stress imposed by increasing water temperatures. In this study, we examined plasticity in heart morphology and function in juvenile Atlantic salmon (Salmo salar) reared under control (+0°C) or elevated (+4°C) temperatures. Using noninvasive Doppler echocardiography, we measured the effect of acute warming on maximum heart rate, stroke distance, and derived cardiac output. A 4°C increase in average developmental temperature resulted in a>5°C increase in the Arrhenius breakpoint temperature for maximum heart rate and enabled the hearts of these fish to continue beating rhythmically to temperatures approximately 2°C higher than control fish. However, these differences in thermal performance were not associated with plasticity in maximum cardiovascular capacity, as peak measures of heart rate, stroke distance, and derived cardiac output did not differ between temperature treatments. Histological analysis of the heart revealed that while ventricular roundness and relative ventricle size did not differ between treatments, the proportion of compact myocardium in the ventricular wall was significantly greater in fish raised at elevated temperatures. Our findings contribute to the growing understanding of how the thermal environment can affect phenotypes later in life and identifies a morphological strategy that may help fishes cope with acute thermal stress.
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Affiliation(s)
- Carlie A Muir
- Department of Biology, Western University, London, ON, Canada
| | - Shawn R Garner
- Department of Biology, Western University, London, ON, Canada
| | | | - Bryan D Neff
- Department of Biology, Western University, London, ON, Canada
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7
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Ekström A, Prystay TS, Abrams AEI, Carbajal A, Holder PE, Zolderdo AJ, Sandblom E, Cooke SJ. Impairment of branchial and coronary blood flow reduces reproductive fitness, but not cardiac performance in paternal smallmouth bass (Micropterus dolomieu). Comp Biochem Physiol A Mol Integr Physiol 2022; 267:111165. [PMID: 35167975 DOI: 10.1016/j.cbpa.2022.111165] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 02/09/2022] [Accepted: 02/09/2022] [Indexed: 11/18/2022]
Abstract
The capacity to extract oxygen from the water, and the ability of the heart to drive tissue oxygen transport, are fundamental determinants of important life-history performance traits in fish. Cardiac performance is in turn dependent on the heart's own oxygen supply, which in some teleost species is partly delivered via a coronary circulation originating directly from the gills that perfuses the heart, and is crucial for cardiac, metabolic and locomotory capacities. It is currently unknown, however, how a compromised branchial blood flow (e.g., by angling-induced hook damage to the gills), constraining oxygen uptake and coronary blood flow, affects the energetically demanding parental care behaviours and reproductive fitness in fish. Here, we tested the hypothesis that blocking ¼ of the branchial blood flow and abolishing coronary blood flow would negatively affect parental care behaviours, cardiac performance (heart rate metrics, via implanted Star-Oddi heart rate loggers) and reproductive fitness of paternal smallmouth bass (Micropterus dolomieu). Our findings reveal that branchial/coronary ligation compromised reproductive fitness, as reflected by a lower proportion of broods reaching free-swimming fry and a tendency for a higher nest abandonment rate relative to sham operated control fish. While this was associated with a tendency for a reduced aggression in ligated fish, parental care behaviours were largely unaffected by the ligation. Moreover, the ligation did not impair any of the heart rate performance metrics. Our findings highlight that gill damage may compromise reproductive output of smallmouth bass populations during the spawning season. Yet, the mechanism(s) behind this finding remains elusive.
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Affiliation(s)
- Andreas Ekström
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden.
| | - Tanya S Prystay
- Department of Biology and Institute of Environmental and Interdisciplinary Sciences, Carleton University, Ottawa, ON, Canada
| | - Alice E I Abrams
- Department of Biology and Institute of Environmental and Interdisciplinary Sciences, Carleton University, Ottawa, ON, Canada
| | - Annaïs Carbajal
- Department of Animal Health and Anatomy, Autonomous University of Barcelona, Barcelona, Spain
| | - Peter E Holder
- Department of Biology and Institute of Environmental and Interdisciplinary Sciences, Carleton University, Ottawa, ON, Canada
| | - Aaron J Zolderdo
- Department of Biology and Institute of Environmental and Interdisciplinary Sciences, Carleton University, Ottawa, ON, Canada; Department of Biology, Queen's University Biological Station, Elgin, ON, Canada
| | - Erik Sandblom
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Steven J Cooke
- Department of Biology and Institute of Environmental and Interdisciplinary Sciences, Carleton University, Ottawa, ON, Canada
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8
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Proteomic analysis of temperature-dependent developmental plasticity within the ventricle of juvenile Atlantic salmon (Salmo salar). Curr Res Physiol 2022; 5:344-354. [PMID: 36035983 PMCID: PMC9403292 DOI: 10.1016/j.crphys.2022.07.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 07/20/2022] [Accepted: 07/29/2022] [Indexed: 11/20/2022] Open
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9
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Pandey A, Rajesh M, Baral P, Sarma D, Tripathi PH, Akhtar MS, Ciji A, Dubey MK, Pande V, Sharma P, Kamalam BS. Concurrent changes in thermal tolerance thresholds and cellular heat stress response reveals novel molecular signatures and markers of high temperature acclimation in rainbow trout. J Therm Biol 2021; 102:103124. [PMID: 34863487 DOI: 10.1016/j.jtherbio.2021.103124] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 10/27/2021] [Accepted: 10/30/2021] [Indexed: 01/31/2023]
Abstract
The objective of this study was to better understand the molecular mechanisms which regulate acclimatory responses and thermal safety margins of rainbow trout (Oncorhynchus mykiss) at temperatures above physiological optimum. For this, we investigated the time course of changes in critical thermal tolerance thresholds and associated hepatic and renal transcript abundance of molecular markers related to cellular stress response, during high temperature acclimation. The experimental fish were initially acclimated to 17 °C and later exposed to a gradually raised elevated temperature regime (22 °C) for a period of 30 days. CTmax, CTmin and mRNA expression of candidate markers were examined before the thermal challenge (T0) and over the time-course (days) of high temperature exposure (T1, T3, T7, T15 and T30). With respect to organismal response, CTmax was significantly elevated at T3, but the degree of gain in heat tolerance was not persistent. Contrarily, we observed a gradual loss in cold tolerance with highest CTmin estimate at T30. Based on the time-course of mRNA expression, the studied markers could be categorized into those which were persistently elevated (hsp70a, hsp70b, hspa5, hsp90a, hsp90b, stip1 and serpinh1 in kidney and hsp90b in liver); those which concurred with changes in CTmin (hspbp1, hsp90b, stip1, gr1, hif1a, hyou1, tnfa and tlr5 in kidney); and those which concurred with changes in CTmax (hsp90a, serpinh1, tlr5 and lmo2 in liver). Apparently, transcriptional changes in kidney and liver reflected CTmin and CTmax trend, respectively. Expression profile of stip1 and tlr5 suggest that they are potential novel markers which could reflect thermal limits in rainbow trout. Hepatic metabolic markers were either initially elevated (alt, glud, g6pase1) or down-regulated at different time-points (ast2, gls1, fas, cpt1b, mtor), linked to gluconeogenesis and metabolic depression, respectively. Whereas, growth-axis markers showed no significant differences. Overall, this time-course analysis has revealed potential associations in organismal and tissue-specific cellular response to high temperature acclimation in a thermally sensitive coldwater ectotherm.
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Affiliation(s)
- Anupam Pandey
- ICAR-Directorate of Coldwater Fisheries Research, Bhimtal, 263136, Uttarakhand, India; Department of Biotechnology, Kumaun University, Bhimtal, 263136, Uttarakhand, India
| | - Manchi Rajesh
- ICAR-Directorate of Coldwater Fisheries Research, Bhimtal, 263136, Uttarakhand, India
| | - Pratibha Baral
- ICAR-Directorate of Coldwater Fisheries Research, Bhimtal, 263136, Uttarakhand, India
| | - Debajit Sarma
- ICAR-Directorate of Coldwater Fisheries Research, Bhimtal, 263136, Uttarakhand, India
| | - Priyanka H Tripathi
- ICAR-Directorate of Coldwater Fisheries Research, Bhimtal, 263136, Uttarakhand, India; Department of Biotechnology, Kumaun University, Bhimtal, 263136, Uttarakhand, India
| | - Md Shahbaz Akhtar
- ICAR-Directorate of Coldwater Fisheries Research, Bhimtal, 263136, Uttarakhand, India
| | - Alexander Ciji
- ICAR-Directorate of Coldwater Fisheries Research, Bhimtal, 263136, Uttarakhand, India
| | - Maneesh Kumar Dubey
- ICAR-Directorate of Coldwater Fisheries Research, Bhimtal, 263136, Uttarakhand, India
| | - Veena Pande
- Department of Biotechnology, Kumaun University, Bhimtal, 263136, Uttarakhand, India
| | - Prakash Sharma
- ICAR-Directorate of Coldwater Fisheries Research, Bhimtal, 263136, Uttarakhand, India
| | - Biju Sam Kamalam
- ICAR-Directorate of Coldwater Fisheries Research, Bhimtal, 263136, Uttarakhand, India.
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10
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Zena LA, Ekström A, Gräns A, Olsson C, Axelsson M, Sundh H, Sandblom E. It takes time to heal a broken heart: ventricular plasticity improves heart performance after myocardial infarction in rainbow trout, Oncorhynchus mykiss. J Exp Biol 2021; 224:273477. [PMID: 34792140 DOI: 10.1242/jeb.243578] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 11/12/2021] [Indexed: 12/28/2022]
Abstract
Coronary arteriosclerosis is a common feature of both wild and farmed salmonid fishes and may be linked to stress-induced cardiac pathologies. Yet, the plasticity and capacity for long-term myocardial restructuring and recovery following a restriction in coronary blood supply are unknown. Here, we analyzed the consequences of acute (3 days) and chronic (from 33 to 62 days) coronary occlusion (i.e. coronary artery ligation) on cardiac morphological characteristics and in vivo function in juvenile rainbow trout, Oncorhynchus mykiss. Acute coronary artery occlusion resulted in elevated resting heart rate and decreased inter-beat variability, which are both markers of autonomic dysfunction following acute myocardial ischemia, along with severely reduced heart rate scope (maximum-resting heart rate) relative to sham-operated trout. We also observed a loss of myocardial interstitial collagen and compact myocardium. Following long-term coronary artery ligation, resting heart rate and heart rate scope normalized relative to sham-operated trout. Moreover, a distinct fibrous collagen layer separating the compact myocardium into two layers had formed. This may contribute to maintain ventricular integrity across the cardiac cycle or, alternatively, demark a region of the compact myocardium that continues to receive oxygen from the luminal venous blood. Taken together, we demonstrate that rainbow trout may cope with the aversive effects caused by coronary artery obstruction through plastic ventricular remodeling, which, at least in part, restores cardiac performance and myocardium oxygenation.
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Affiliation(s)
- Lucas A Zena
- Department of Physiology, Institute of Biosciences, University of São Paulo, 05508-090 São Paulo, Brazil.,Department of Biological and Environmental Sciences, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Andreas Ekström
- Department of Biological and Environmental Sciences, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Albin Gräns
- Department of Animal Environment and Health, Swedish University of Agricultural Sciences, Gothenburg 405 30, Sweden
| | - Catharina Olsson
- Department of Biological and Environmental Sciences, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Michael Axelsson
- Department of Biological and Environmental Sciences, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Henrik Sundh
- Department of Biological and Environmental Sciences, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Erik Sandblom
- Department of Biological and Environmental Sciences, University of Gothenburg, 405 30 Gothenburg, Sweden
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11
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Muir CA, Neff BD, Damjanovski S. Adaptation of a mouse Doppler echocardiograph system for assessing cardiac function and thermal performance in a juvenile salmonid. CONSERVATION PHYSIOLOGY 2021; 9:coab070. [PMID: 34512992 PMCID: PMC8415535 DOI: 10.1093/conphys/coab070] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 06/04/2021] [Accepted: 08/11/2021] [Indexed: 06/13/2023]
Abstract
Measures of cardiac performance are pertinent to the study of thermal physiology and exercise in teleosts, particularly as they pertain to migration success. Increased heart rate, stroke volume and cardiac output have previously been linked to improved swimming performance and increased upper thermal tolerance in anadromous salmonids. To assess thermal performance in fishes, it has become commonplace to measure the response of maximum heart rate to warming using electrocardiograms. However, electrocardiograms do not provide insight into the hemodynamic characteristics of heart function that can impact whole-animal performance. Doppler echocardiography is a popular tool used to examine live animal processes, including real-time cardiac function. This method allows for nonsurgical measurements of blood flow velocity through the heart and has been used to detect abnormalities in cardiovascular function, particularly in mammals. Here, we show how a mouse Doppler echocardiograph system can be adapted for use in a juvenile salmonid over a range of temperatures and timeframes. Using this compact, noninvasive system, we measured maximum heart rate, atrioventricular (AV) blood flow velocity, the early flow-atrial flow ratio and stroke distance in juvenile Atlantic salmon (Salmo salar) during acute warming. Using histologically determined measures of AV valve area, we show how stroke distance measurements obtained with this system can be used to calculate ventricular inflow volume and approximate cardiac output. Further, we show how this Doppler system can be used to determine cardiorespiratory thresholds for thermal performance, which are increasingly being used to predict the consequences that warming water temperatures will have on migratory fishes.
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Affiliation(s)
- Carlie A Muir
- Department of Biology, Western University, London, Ontario, Canada N6A 5B7
| | - Bryan D Neff
- Department of Biology, Western University, London, Ontario, Canada N6A 5B7
| | - Sashko Damjanovski
- Department of Biology, Western University, London, Ontario, Canada N6A 5B7
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12
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McArley TJ, Morgenroth D, Zena LA, Ekström AT, Sandblom E. Normoxic limitation of maximal oxygen consumption rate, aerobic scope and cardiac performance in exhaustively exercised rainbow trout (Oncorhynchus mykiss). J Exp Biol 2021; 224:271087. [PMID: 34323276 DOI: 10.1242/jeb.242614] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 06/25/2021] [Indexed: 01/22/2023]
Abstract
In fish, maximum O2 consumption rate (ṀO2,max) and aerobic scope can be expanded following exhaustive exercise in hyperoxia; however, the mechanisms explaining this are yet to be identified. Here, in exhaustively exercised rainbow trout (Oncorhynchus mykiss), we assessed the influence of hyperoxia on ṀO2,max, aerobic scope, cardiac function and blood parameters to address this knowledge gap. Relative to normoxia, ṀO2,max was 33% higher under hyperoxia, and this drove a similar increase in aerobic scope. Cardiac output was significantly elevated under hyperoxia at ṀO2,max because of increased stroke volume, indicating that hyperoxia released a constraint on cardiac contractility apparent with normoxia. Thus, hyperoxia improved maximal cardiac performance, thereby enhancing tissue O2 delivery and allowing a higher ṀO2,max. Venous blood O2 partial pressure (PvO2) was elevated in hyperoxia at ṀO2,max, suggesting a contribution of improved luminal O2 supply in enhanced cardiac contractility. Additionally, despite reduced haemoglobin and higher PvO2, hyperoxia treated fish retained a higher arterio-venous O2 content difference at ṀO2,max. This may have been possible because of hyperoxia offsetting declines in arterial oxygenation that are known to occur following exhaustive exercise in normoxia. If this occurs, increased contractility at ṀO2,max with hyperoxia may also relate to an improved O2 supply to the compact myocardium via the coronary artery. Our findings show ṀO2,max and aerobic scope may be limited in normoxia following exhaustive exercise as a result of constrained maximal cardiac performance and highlight the need to further examine whether or not exhaustive exercise protocols are suitable for eliciting ṀO2,max and estimating aerobic scope in rainbow trout.
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Affiliation(s)
- Tristan J McArley
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, 405 30 Gothenburg, Sweden
| | - Daniel Morgenroth
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, 405 30 Gothenburg, Sweden
| | - Lucas A Zena
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, 405 30 Gothenburg, Sweden
| | - Andreas T Ekström
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, 405 30 Gothenburg, Sweden
| | - Erik Sandblom
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, 405 30 Gothenburg, Sweden
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13
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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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14
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Morgenroth D, McArley T, Gräns A, Axelsson M, Sandblom E, Ekström A. Coronary blood flow influences tolerance to environmental extremes in fish. J Exp Biol 2021; 224:jeb.239970. [PMID: 33688058 DOI: 10.1242/jeb.239970] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 03/03/2021] [Indexed: 12/16/2022]
Abstract
Approximately half of all fishes have, in addition to the luminal venous O2 supply, a coronary circulation supplying the heart with fully oxygenated blood. Yet, it is not fully understood how coronary O2 delivery affects tolerance to environmental extremes such as warming and hypoxia. Hypoxia reduces arterial oxygenation, while warming increases overall tissue O2 demand. Thus, as both stressors are associated with reduced venous O2 supply to the heart, we hypothesised that coronary flow benefits hypoxia and warming tolerance. To test this hypothesis, we blocked coronary blood flow (via surgical coronary ligation) in rainbow trout (Oncorhynchus mykiss) and assessed how in vivo cardiorespiratory performance and whole-animal tolerance to acute hypoxia and warming was affected. While coronary ligation reduced routine stroke volume relative to trout with intact coronaries, cardiac output was maintained by an increase in heart rate. However, in hypoxia, coronary-ligated trout were unable to increase stroke volume to maintain cardiac output when bradycardia developed, which was associated with a slightly reduced hypoxia tolerance. Moreover, during acute warming, coronary ligation caused cardiac function to collapse at lower temperatures and reduced overall heat tolerance relative to trout with intact coronary arteries. We also found a positive relationship between individual hypoxia and heat tolerance across treatment groups, and tolerance to both environmental stressors was positively correlated with cardiac performance. Collectively, our findings show that coronary perfusion improves cardiac O2 supply and therefore cardiovascular function at environmental extremes, which benefits tolerance to natural and anthropogenically induced environmental perturbations.
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Affiliation(s)
- Daniel Morgenroth
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, 405 30 Gothenburg, Sweden
| | - Tristan McArley
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, 405 30 Gothenburg, Sweden
| | - Albin Gräns
- Department of Animal Environment and Health, Swedish University of Agricultural Sciences, 532 23 Skara, Sweden
| | - Michael Axelsson
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, 405 30 Gothenburg, Sweden
| | - Erik Sandblom
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, 405 30 Gothenburg, Sweden
| | - Andreas Ekström
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, 405 30 Gothenburg, Sweden
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15
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Adrenergic tone benefits cardiac performance and warming tolerance in two teleost fishes that lack a coronary circulation. J Comp Physiol B 2021; 191:701-709. [PMID: 33738526 PMCID: PMC8241749 DOI: 10.1007/s00360-021-01359-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 02/04/2021] [Accepted: 02/22/2021] [Indexed: 01/14/2023]
Abstract
Tolerance to acute environmental warming in fish is partly governed by the functional capacity of the heart to increase systemic oxygen delivery at high temperatures. However, cardiac function typically deteriorates at high temperatures, due to declining heart rate and an impaired capacity to maintain or increase cardiac stroke volume, which in turn has been attributed to a deterioration of the electrical conductivity of cardiac tissues and/or an impaired cardiac oxygen supply. While autonomic regulation of the heart may benefit cardiac function during warming by improving myocardial oxygenation, contractility and conductivity, the role of these processes for determining whole animal thermal tolerance is not clear. This is in part because interpretations of previous pharmacological in vivo experiments in salmonids are ambiguous and were confounded by potential compensatory increases in coronary oxygen delivery to the myocardium. Here, we tested the previously advanced hypothesis that cardiac autonomic control benefits heart function and acute warming tolerance in perch (Perca fluviatilis) and roach (Rutilus rutilus); two species that lack coronary arteries and rely entirely on luminal venous oxygen supplies for cardiac oxygenation. Pharmacological blockade of β-adrenergic tone lowered the upper temperature where heart rate started to decline in both species, marking the onset of cardiac failure, and reduced the critical thermal maximum (CTmax) in perch. Cholinergic (muscarinic) blockade had no effect on these thermal tolerance indices. Our findings are consistent with the hypothesis that adrenergic stimulation improves cardiac performance during acute warming, which, at least in perch, increases acute thermal tolerance.
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16
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Lefevre S, Wang T, McKenzie DJ. The role of mechanistic physiology in investigating impacts of global warming on fishes. J Exp Biol 2021; 224:224/Suppl_1/jeb238840. [PMID: 33627469 DOI: 10.1242/jeb.238840] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Warming of aquatic environments as a result of climate change is already having measurable impacts on fishes, manifested as changes in phenology, range shifts and reductions in body size. Understanding the physiological mechanisms underlying these seemingly universal patterns is crucial if we are to reliably predict the fate of fish populations with future warming. This includes an understanding of mechanisms for acute thermal tolerance, as extreme heatwaves may be a major driver of observed effects. The hypothesis of gill oxygen limitation (GOL) is claimed to explain asymptotic fish growth, and why some fish species are decreasing in size with warming; but its underlying assumptions conflict with established knowledge and direct mechanistic evidence is lacking. The hypothesis of oxygen- and capacity-limited thermal tolerance (OCLTT) has stimulated a wave of research into the role of oxygen supply capacity and thermal performance curves for aerobic scope, but results vary greatly between species, indicating that it is unlikely to be a universal mechanism. As thermal performance curves remain important for incorporating physiological tolerance into models, we discuss potentially fruitful alternatives to aerobic scope, notably specific dynamic action and growth rate. We consider the limitations of estimating acute thermal tolerance by a single rapid measure whose mechanism of action is not known. We emphasise the continued importance of experimental physiology, particularly in advancing our understanding of underlying mechanisms, but also the challenge of making this knowledge relevant to the more complex reality.
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Affiliation(s)
- Sjannie Lefevre
- Section for Physiology and Cell Biology, Department of Biosciences, University of Oslo, 0316 Oslo, Norway
| | - Tobias Wang
- Department of Biology - Zoophysiology, Aarhus University, 8000 Aarhus C, Denmark
| | - David J McKenzie
- Marine Biodiversity, Exploitation and Conservation (MARBEC), Université de Montpellier, CNRS, Ifremer, IRD, 34000 Montpellier, France
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17
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Little AG, Loughland I, Seebacher F. What do warming waters mean for fish physiology and fisheries? JOURNAL OF FISH BIOLOGY 2020; 97:328-340. [PMID: 32441327 DOI: 10.1111/jfb.14402] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 04/30/2020] [Accepted: 05/20/2020] [Indexed: 06/11/2023]
Abstract
Environmental signals act primarily on physiological systems, which then influence higher-level functions such as movement patterns and population dynamics. Increases in average temperature and temperature variability associated with global climate change are likely to have strong effects on fish physiology and thereby on populations and fisheries. Here we review the principal mechanisms that transduce temperature signals and the physiological responses to those signals in fish. Temperature has a direct, thermodynamic effect on biochemical reaction rates. Nonetheless, plastic responses to longer-term thermal signals mean that fishes can modulate their acute thermal responses to compensate at least partially for thermodynamic effects. Energetics are particularly relevant for growth and movement, and therefore for fisheries, and temperature can have pronounced effects on energy metabolism. All energy (ATP) production is ultimately linked to mitochondria, and temperature has pronounced effects on mitochondrial efficiency and maximal capacities. Mitochondria are dependent on oxygen as the ultimate electron acceptor so that cardiovascular function and oxygen delivery link environmental inputs with energy metabolism. Growth efficiency, that is the conversion of food into tissue, changes with temperature, and there are indications that warmer water leads to decreased conversion efficiencies. Moreover, movement and migration of fish relies on muscle function, which is partially dependent on ATP production but also on intracellular calcium cycling within the myocyte. Neuroendocrine processes link environmental signals to regulated responses at the level of different tissues, including muscle. These physiological processes within individuals can scale up to population responses to climate change. A mechanistic understanding of thermal responses is essential to predict the vulnerability of species and populations to climate change.
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Affiliation(s)
| | - Isabella Loughland
- School of Life and Environmental Sciences A08, University of Sydney, Sydney, Australia
| | - Frank Seebacher
- School of Life and Environmental Sciences A08, University of Sydney, Sydney, Australia
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18
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Little AG, Hardison E, Kraskura K, Dressler T, Prystay TS, Hendriks B, Pruitt JN, Farrell AP, Cooke SJ, Patterson DA, Hinch SG, Eliason EJ. Reduced lactate dehydrogenase activity in the heart and suppressed sex hormone levels are associated with female-biased mortality during thermal stress in Pacific salmon. J Exp Biol 2020; 223:jeb214841. [PMID: 32561626 DOI: 10.1242/jeb.214841] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 06/10/2020] [Indexed: 11/20/2022]
Abstract
Female-biased mortality has been repeatedly reported in Pacific salmon during their upriver migration in both field studies and laboratory holding experiments, especially in the presence of multiple environmental stressors, including thermal stress. Here, we used coho salmon (Oncorhynchus kisutch) to test whether females exposed to elevated water temperatures (18°C) (i) suppress circulating sex hormones (testosterone, 11-ketotestosterone and estradiol), owing to elevated cortisol levels, (ii) have higher activities of enzymes supporting anaerobic metabolism (e.g. lactate dehydrogenase, LDH), (iii) have lower activities of enzymes driving oxidative metabolism (e.g. citrate synthase, CS) in skeletal and cardiac muscle, and (iv) have more oxidative stress damage and reduced capacity for antioxidant defense [lower catalase (CAT) activity]. We found no evidence that a higher susceptibility to oxidative stress contributes to female-biased mortality at warm temperatures. We did, however, find that females had significantly lower cardiac LDH and that 18°C significantly reduced plasma levels of testosterone and estradiol, especially in females. We also found that relative gonad size was significantly lower in the 18°C treatment regardless of sex, whereas relative liver size was significantly lower in females held at 18°C. Further, relative spleen size was significantly elevated in the 18°C treatments across both sexes, with larger warm-induced increases in females. Our results suggest that males may better tolerate bouts of cardiac hypoxia at high temperature, and that thermal stress may also disrupt testosterone- and estradiol-mediated protein catabolism, and the immune response (larger spleens), in migratory female salmon.
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Affiliation(s)
- A G Little
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - E Hardison
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - K Kraskura
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - T Dressler
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - T S Prystay
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental and Interdisciplinary Science, Carleton University, Ottawa, ON K1S 5B6, Canada
| | - B Hendriks
- Fisheries and Oceans Canada, Cooperative Resource Management Institute, School of Resource and Environmental Management, Simon Fraser University, Burnaby, BC, Canada V5A 1S6
| | - J N Pruitt
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontario, Canada L8S 4K1
| | - A P Farrell
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
- Department of Zoology and Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
| | - S J Cooke
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental and Interdisciplinary Science, Carleton University, Ottawa, ON K1S 5B6, Canada
| | - D A Patterson
- Fisheries and Oceans Canada, Cooperative Resource Management Institute, School of Resource and Environmental Management, Simon Fraser University, Burnaby, BC, Canada V5A 1S6
| | - S G Hinch
- Pacific Salmon Ecology and Conservation Laboratory, Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
| | - E J Eliason
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
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19
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Ekström A, Gräns A, Sandblom E. Can´t beat the heat? Importance of cardiac control and coronary perfusion for heat tolerance in rainbow trout. J Comp Physiol B 2019; 189:10.1007/s00360-019-01243-7. [PMID: 31707423 DOI: 10.1007/s00360-019-01243-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 10/11/2019] [Accepted: 10/24/2019] [Indexed: 12/11/2022]
Abstract
Coronary perfusion and cardiac autonomic regulation may benefit myocardial oxygen delivery and thermal performance of the teleost heart, and thus influence whole animal heat tolerance. Yet, no study has examined how coronary perfusion affects cardiac output during warming in vivo. Moreover, while β-adrenergic stimulation could protect cardiac contractility, and cholinergic decrease in heart rate may enhance myocardial oxygen diffusion at critically high temperatures, previous studies in rainbow trout (Oncorhynchus mykiss) using pharmacological antagonists to block cholinergic and β-adrenergic regulation showed contradictory results with regard to cardiac performance and heat tolerance. This could reflect intra-specific differences in the extent to which altered coronary perfusion buffered potential negative effects of the pharmacological blockade. Here, we first tested how cardiac performance and the critical thermal maximum (CTmax) were affected following a coronary ligation. We then assessed how these performances were influenced by pharmacological cholinergic or β-adrenergic blockade, hypothesising that the effects of the pharmacological treatment would be more pronounced in coronary ligated trout compared to trout with intact coronaries. Coronary blockade reduced CTmax by 1.5 °C, constrained stroke volume and cardiac output across temperatures, led to earlier cardiac failure and was associated with reduced blood oxygen-carrying capacity. Nonetheless, CTmax and the temperatures for cardiac failure were not affected by autonomic blockade. Collectively, our data show that coronary perfusion improves heat tolerance and cardiac performance in trout, while evidence for beneficial effects of altered cardiac autonomic tone during warming remains inconclusive.
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Affiliation(s)
- Andreas Ekström
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, 405 30, Göteborg, Sweden.
| | - Albin Gräns
- Department of Animal Environment and Health, Swedish University of Agricultural Sciences, Göteborg, Sweden
| | - Erik Sandblom
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, 405 30, Göteborg, Sweden
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20
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Ekström A, Axelsson M, Gräns A, Brijs J, Sandblom E. Importance of the coronary circulation for cardiac and metabolic performance in rainbow trout ( Oncorhynchus mykiss). Biol Lett 2019; 14:rsbl.2018.0063. [PMID: 30045901 DOI: 10.1098/rsbl.2018.0063] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 06/26/2018] [Indexed: 02/02/2023] Open
Abstract
Cardiac oxygenation is achieved via both coronary arterial and luminal venous oxygen supply routes in many fish species. However, the relative importance of these supplies for cardiac and aerobic metabolic performance is not fully understood. Here, we investigated how coronary artery ligation in rainbow trout (Oncorhynchus mykiss), implanted with heart rate loggers, affected cardiorespiratory performance in vivo While coronary ligation significantly elevated resting heart rate, the standard metabolic rate was unchanged compared to sham-treated controls. However, coronary ligation reduced the maximum metabolic rate while heart rate remained unchanged following enforced exercise. Thus, coronary ligation reduced metabolic and heart rate scopes by 29% and 74%, respectively. Our findings highlight the importance of coronary oxygen supply for overall cardiorespiratory performance in salmonid fish, and suggest that pathological conditions that impair coronary flow (e.g. coronary arteriosclerosis) constrain the ability of fish to cope with metabolically demanding challenges such as spawning migrations and environmental warming.
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Affiliation(s)
- Andreas Ekström
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Michael Axelsson
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Albin Gräns
- Department of Animal Environment and Health, Swedish University of Agricultural Sciences, Skara, Sweden
| | - Jeroen Brijs
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden.,Department of Animal Environment and Health, Swedish University of Agricultural Sciences, Skara, Sweden
| | - Erik Sandblom
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
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21
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Gilbert MJH, Rani V, McKenzie SM, Farrell AP. Autonomic cardiac regulation facilitates acute heat tolerance in rainbow trout: in situ and in vivo support. ACTA ACUST UNITED AC 2019; 222:jeb.194365. [PMID: 31015284 DOI: 10.1242/jeb.194365] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 04/10/2019] [Indexed: 12/27/2022]
Abstract
Acute warming in fish increases heart rate (f H) and cardiac output to peak values, after which performance plateaus or declines and arrhythmia may occur. This cardiac response can place a convective limitation on systemic oxygen delivery at high temperatures. To test the hypothesis that autonomic cardiac regulation protects cardiac performance in rainbow trout during acute warming, we investigated adrenergic and cholinergic regulation during the onset and progression of cardiac limitations. We explored the direct effects of adrenergic stimulation by acutely warming an in situ working perfused heart until arrhythmia occurred, cooling the heart to restore rhythmicity and rewarming with increasing adrenergic stimulation. Adrenergic stimulation produced a clear, dose-dependent increase in the temperature and peak f H achieved prior to the onset of arrhythmia. To examine how this adrenergic protection functions in conjunction with cholinergic vagal inhibition in vivo, rainbow trout fitted with ECG electrodes were acutely warmed in a respirometer until they lost equilibrium (CTmax) with and without muscarinic (atropine) and β-adrenergic (sotalol) antagonists. Trout exhibited roughly equal and opposing cholinergic and adrenergic tone on f H that persisted up to critical temperatures. β-Adrenergic blockade significantly lowered peak f H by 14-17%, while muscarinic blockade significantly lowered the temperature for peak f H by 2.0°C. Moreover, muscarinic and β-adrenergic blockers injected individually or together significantly reduced CTmax by up to 3°C, indicating for the first time that cardiac adrenergic stimulation and cholinergic inhibition can enhance acute heat tolerance in rainbow trout at the level of the heart and the whole animal.
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Affiliation(s)
- Matthew J H Gilbert
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4
| | - Varsha Rani
- Faculty of Land and Food Systems, University of British Columbia, 2357 Main Mall, Vancouver, BC, Canada V6T 1Z4
| | - Sean M McKenzie
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4
| | - Anthony P Farrell
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4.,Faculty of Land and Food Systems, University of British Columbia, 2357 Main Mall, Vancouver, BC, Canada V6T 1Z4
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22
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McArley TJ, Hickey AJR, Herbert NA. Hyperoxia increases maximum oxygen consumption and aerobic scope of intertidal fish facing acutely high temperatures. ACTA ACUST UNITED AC 2018; 221:jeb.189993. [PMID: 30254026 DOI: 10.1242/jeb.189993] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 09/18/2018] [Indexed: 12/17/2022]
Abstract
Daytime low tides that lead to high-temperature events in stranded rock pools often co-occur with algae-mediated hyperoxia as a result of strong solar radiation. Recent evidence shows aerobic metabolic scope (MS) can be expanded under hyperoxia in fish but so far this possibility has not been examined in intertidal species despite being an ecologically relevant scenario. Furthermore, it is unknown whether hyperoxia increases the upper thermal tolerance limits of intertidal fish and, therefore, their ability to withstand extreme high-temperature events. Therefore, we measured the metabolic response (mass-specific rate of oxygen consumption, Ṁ O2 ) to thermal ramping (21-29°C) and the upper thermal tolerance limit (U TL) of two intertidal triplefin fishes (Bellapiscis medius and Forsterygion lapillum) under hyperoxia and normoxia. Hyperoxia increased maximal oxygen consumption (Ṁ O2,max) and MS of each species at ambient temperature (21°C) but also after thermal ramping to elevated temperatures such as those observed in rock pools (29°C). While hyperoxia did not provide a biologically meaningful increase in upper thermal tolerance of either species (>31°C under all conditions), the observed expansion of MS at 29°C under hyperoxia could potentially benefit the aerobic performance, and hence the growth and feeding potential, etc., of intertidal fish at non-critical temperatures. That hyperoxia does not increase upper thermal tolerance in a meaningful way is cause for concern as climate change is expected to drive more extreme rock pool temperatures in the future and this could present a major challenge for these species.
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Affiliation(s)
- Tristan J McArley
- Institute of Marine Science, University of Auckland, Leigh, Warkworth 0941, New Zealand
| | - Anthony J R Hickey
- School of Biological Sciences, University of Auckland, 3a Symonds Street, Thomas Building, Auckland 1010, New Zealand
| | - Neill A Herbert
- Institute of Marine Science, University of Auckland, Leigh, Warkworth 0941, New Zealand
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Pörtner HO, Bock C, Mark FC. Oxygen- and capacity-limited thermal tolerance: bridging ecology and physiology. J Exp Biol 2017; 220:2685-2696. [DOI: 10.1242/jeb.134585] [Citation(s) in RCA: 289] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2016] [Accepted: 05/12/2017] [Indexed: 12/19/2022]
Abstract
ABSTRACT
Observations of climate impacts on ecosystems highlight the need for an understanding of organismal thermal ranges and their implications at the ecosystem level. Where changes in aquatic animal populations have been observed, the integrative concept of oxygen- and capacity-limited thermal tolerance (OCLTT) has successfully characterised the onset of thermal limits to performance and field abundance. The OCLTT concept addresses the molecular to whole-animal mechanisms that define thermal constraints on the capacity for oxygen supply to the organism in relation to oxygen demand. The resulting ‘total excess aerobic power budget’ supports an animal's performance (e.g. comprising motor activity, reproduction and growth) within an individual's thermal range. The aerobic power budget is often approximated through measurements of aerobic scope for activity (i.e. the maximum difference between resting and the highest exercise-induced rate of oxygen consumption), whereas most animals in the field rely on lower (i.e. routine) modes of activity. At thermal limits, OCLTT also integrates protective mechanisms that extend time-limited tolerance to temperature extremes – mechanisms such as chaperones, anaerobic metabolism and antioxidative defence. Here, we briefly summarise the OCLTT concept and update it by addressing the role of routine metabolism. We highlight potential pitfalls in applying the concept and discuss the variables measured that led to the development of OCLTT. We propose that OCLTT explains why thermal vulnerability is highest at the whole-animal level and lowest at the molecular level. We also discuss how OCLTT captures the thermal constraints on the evolution of aquatic animal life and supports an understanding of the benefits of transitioning from water to land.
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Affiliation(s)
- Hans-O. Pörtner
- Section of Integrative Ecophysiology, Biosciences, Alfred-Wegener-Institute, Bremerhaven D-27570, Germany
| | - Christian Bock
- Section of Integrative Ecophysiology, Biosciences, Alfred-Wegener-Institute, Bremerhaven D-27570, Germany
| | - Felix C. Mark
- Section of Integrative Ecophysiology, Biosciences, Alfred-Wegener-Institute, Bremerhaven D-27570, Germany
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Powell MD, Yousaf MN. Cardiovascular Effects of Disease: Parasites and Pathogens. FISH PHYSIOLOGY 2017. [DOI: 10.1016/bs.fp.2017.09.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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