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Auteur (up) Jourdan-Pineau, H.; Dupont-Prinet, A.; Claireaux, G.; McKenzie, D.J.
Titre An Investigation of Metabolic Prioritization in the European Sea Bass, Dicentrarchus labrax Type Article scientifique
Année 2010 Publication Revue Abrégée Physiol. Biochem. Zool.
Volume 83 Numéro 1 Pages 68-77
Mots-Clés Hypoxia; blood-flow; cardiac-performance; dynamic action; largemouth bass; oxygen-consumption; respiratory metabolism; salmo-gairdneri; swimming performance; trout oncorhynchus-mykiss
Résumé We investigated the ability of European sea bass (Dicentrarchus labrax) to respond simultaneously to the metabolic demands of specific dynamic action (SDA) and aerobic exercise and how this was influenced by moderate hypoxia (50% air saturation). At 3 h after feeding in normoxia at 20 degrees C, SDA raised the instantaneous oxygen uptake (Mo(2)) of sea bass by 47% +/- 18% (mean +/- SEM, N = 7) above their standard metabolic rate (SMR) when fasted. This metabolic load was sustained throughout an incremental exercise protocol until fatigue, with a 14% +/- 3% increase in their maximum aerobic metabolic rate (MMR) relative to their fasted rate. Their incremental critical swimming speed (U(crit)) did not differ between fasted and fed states. Thus, in normoxia, the bass were able to meet the combined oxygen demands of SDA and aerobic exercise. In hypoxia, the sea bass suffered a significant decline in MMR and U(crit) relative to their normoxic performance. The SDA response was similar to normoxia (84% +/- 24% above fasted SMR at 3 h after feeding), but although this load was sustained at low swimming speeds, it gradually disappeared as swimming speed increased. As a result, the hypoxic sea bass exhibited no difference in their fasted versus fed MMR. Hypoxic U(crit) did not, however, differ between fasted and fed states, indicating that the sea bass deferred their SDA to maintain exercise performance. The results demonstrate that, in normoxia, the sea bass possesses excess cardiorespiratory capacity beyond that required for maximal aerobic exercise. The excess capacity is lost when oxygen availability is limited in hypoxia, and, under these conditions, the sea bass prioritize exercise performance. Thus, environmental conditions (oxygen availability) had a significant effect on patterns of oxygen allocation in sea bass and revealed intrinsic prioritization among conflicting metabolic demands.
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ISSN 1522-2152 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 436
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Auteur (up) Lefevre, S.; Mckenzie, D.J.; Nilsson, G.E.
Titre Models projecting the fate of fish populations under climate change need to be based on valid physiological mechanisms Type Article scientifique
Année 2017 Publication Revue Abrégée Glob. Change Biol.
Volume 23 Numéro 9 Pages 3449-3459
Mots-Clés aerobic scope; coryphaena-hippurus; energy-demand teleosts; gadus-morhua l; gill surface area; growth; makaira-nigricans; marlin tetrapturus-albidus; metabolism; metabolism-size relationship; oxygen consumption; oxygen-consumption; ram ventilation; Respiration; scaling; swimming performance; tuna katsuwonus-pelamis
Résumé Some recent modelling papers projecting smaller fish sizes and catches in a warmer future are based on erroneous assumptions regarding (i) the scaling of gills with body mass and (ii) the energetic cost of 'maintenance'. Assumption (i) posits that insurmountable geometric constraints prevent respiratory surface areas from growing as fast as body volume. It is argued that these constraints explain allometric scaling of energy metabolism, whereby larger fishes have relatively lower mass-specific metabolic rates. Assumption (ii) concludes that when fishes reach a certain size, basal oxygen demands will not be met, because of assumption (i). We here demonstrate unequivocally, by applying accepted physiological principles with reference to the existing literature, that these assumptions are not valid. Gills are folded surfaces, where the scaling of surface area to volume is not constrained by spherical geometry. The gill surface area can, in fact, increase linearly in proportion to gill volume and body mass. We cite the large body of evidence demonstrating that respiratory surface areas in fishes reflect metabolic needs, not vice versa, which explains the large interspecific variation in scaling of gill surface areas. Finally, we point out that future studies basing their predictions on models should incorporate factors for scaling of metabolic rate and for temperature effects on metabolism, which agree with measured values, and should account for interspecific variation in scaling and temperature effects. It is possible that some fishes will become smaller in the future, but to make reliable predictions the underlying mechanisms need to be identified and sought elsewhere than in geometric constraints on gill surface area. Furthermore, to ensure that useful information is conveyed to the public and policymakers about the possible effects of climate change, it is necessary to improve communication and congruity between fish physiologists and fisheries scientists.
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Volume de collection Numéro de collection Edition
ISSN 1354-1013 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 2169
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Auteur (up) Marras, S.; Killen, S.S.; Claireaux, G.; Domenici, P.; McKenzie, D.J.
Titre Behavioural and kinematic components of the fast-start escape response in fish: individual variation and temporal repeatability Type Article scientifique
Année 2011 Publication Revue Abrégée J. Exp. Biol.
Volume 214 Numéro 18 Pages 3102-3110
Mots-Clés anaerobic performance; anaerobic swimming performance; body form; dicentrarchus-labrax; escape response; european sea bass; fast start; fish; gambusia-affinis; individual variation; locomotor performance; morphology; poecilia-reticulata; rainbow-trout; repeatability; sea bass; stereotype; swimming performance; teleost fish
Résumé Inter-individual variation in physiological performance traits, which is stable over time, can be of potential ecological and evolutionary significance. The fish escape response is interesting in this regard because it is a performance trait for which inter-individual variation may determine individual survival. The temporal stability of such variation is, however, largely unexplored. We quantified individual variation of various components of the escape response in a population of European sea bass (Dicentrarchus labrax), considering both non-locomotor (responsiveness and latency) and locomotor (speed, acceleration, turning rate, turning angle and distance travelled in a fixed time, D(esc)) variables. We assessed whether variation in performance was temporally stable and we searched for any trade-offs among the components of the response that might explain why the variation persisted in the population. The coefficient of variation was high for all components, from 23% for turning rate to 41% for D(esc), highlighting the non-stereotypic nature of the response. Individual performance for all variables was significantly repeatable over five sequential responses at 30min intervals, and also repeatable after a 30 day interval for most of the components. This indicates that the variation is intrinsic to the individuals, but there was no evidence for trade-offs amongst the components of the response, suggesting that, if trade-offs exist, they must be against other ecologically important behavioural or performance traits.
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Langue English Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 0022-0949 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 458
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Auteur (up) McKenzie, D.J.; Hoglund, E.; Dupont-Prinet, A.; Larsen, B.K.; Skov, P.V.; Pedersen, P.B.; Jokumsen, A.
Titre Effects of stocking density and sustained aerobic exercise on growth, energetics and welfare of rainbow trout Type Article scientifique
Année 2012 Publication Revue Abrégée Aquaculture
Volume 338 Numéro Pages 216-222
Mots-Clés Aerobic scope; charr salvelinus-alpinus; Cortisol; Critical swimming speed; current issues; feeding-behavior; fish welfare; juvenile arctic charr; oncorhynchus-mykiss; respiratory physiology; respirometry; salmon salmo-salar; Stress; stress-response; swimming performance; Welfare indicator
Résumé Two stocking densities, “low” (L, between similar to 19 and similar to 25 kg m(-3)) and “high” (H, between similar to 75 and similar to 100 kg m(-3)) were compared for effects on specific growth rate (SGR), feed conversion, energetics and welfare of rainbow trout reared at 14 degrees C either in static water (S) or swimming in a gentle current of similar to 0.9 bodylengths s(-1) (C). Trout (initial mass similar to 110 g) were reared for 9 weeks in circular tanks (volume 0.6 m(3)), in triplicate of four conditions (LS, LC, HS, HC). Fish were fed ad-libitum daily: waste pellets were swirl-collected at the outflow to calculate feed intake. SGR was measured each three weeks for the last six weeks of the trial. The tanks functioned as intermittent-stopped flow respirometers, to permit metabolic rate to be measured as instantaneous oxygen uptake once per hour. Mean (+/-SD) SGR was significantly lower at H than L (1.51 +/- 0.03 vs 1.44 +/- 0.04% day(-1), respectively, n = 6) and lowest in HC. When compared over a similar interval of mass gain, H groups had approximately 25% higher metabolic rates than L, with the highest rates in the HC condition. As a result, fish in the H groups dissipated a greater amount of feed energy as metabolism and, across all groups, there was a direct negative relationship between the quantity of energy dissipated and their SCR. There was no evidence of a neuroendocrine stress response, plasma cortisol was around 1 ng ml(-1) in all conditions. An acute crowding stress increased plasma cortisol to above 120 ng ml(-1) in all groups, but C groups recovered to control levels within 8 h whereas S groups required 20 h. Respirometry on individuals revealed that H fish had approximately 14% higher metabolic rates than L fish, indicating that increased metabolic rate in rearing tanks was in part physiological. The H groups had approximately 15% lower critical swimming speeds than the L groups which, together with their raised metabolic rate, indicated a physiological impairment Thus, high density reduced SGR by raising energy dissipation, at least partially as a physiological response by the fish, although there was no evidence of an endocrine stress response. The only beneficial effect of C was in recovery from acute stress. (C) 2012 Elsevier B.V. All rights reserved.
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Volume de collection Numéro de collection Edition
ISSN 0044-8486 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 1431
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Auteur (up) McKenzie, D.J.; Steffensen, J.F.; Taylor, E.W.; Abe, A.S.
Titre The contribution of air breathing to aerobic scope and exercise performance in the banded knifefish Gymnotus carapo L Type Article scientifique
Année 2012 Publication Revue Abrégée J. Exp. Biol.
Volume 215 Numéro 8 Pages 1323-1330
Mots-Clés Hypoxia; amia-calva; aquatic hypoxia; bass dicentrarchus-labrax; cardiac-performance; critical swimming speed; european sea-bass; megalops-cyprinoides; metabolic rate; oxygen uptake; oxygen-tensions; rainbow-trout; respiratory mode; respirometry; swimming performance
Résumé The contribution of air breathing to aerobic metabolic scope and exercise performance was investigated in a teleost with bimodal respiration, the banded knifefish, submitted to a critical swimming speed (U-crit) protocol at 30 degrees C. Seven individuals (mean +/- s.e.m. mass 89 +/- 7. g, total length 230 +/- 4. mm) achieved a U-crit of 2.1 +/- 1. body. lengths. (BL). s(-1) and an active metabolic rate (AMR) of 350 +/- 21. mg. kg(-1). h(-1), with 38 +/- 6% derived from air breathing. All of the knifefish exhibited a significant increase in air-breathing frequency (f(AB)) with swimming speed. If denied access to air in normoxia, these individuals achieved a U-crit of 2.0 +/- 0.2. BL. s(-1) and an AMR of 368 +/- 24. mg. kg(-1). h(-1) by gill ventilation alone. In normoxia, therefore, the contribution of air breathing to scope and exercise was entirely facultative. In aquatic hypoxia (P-O2=4. kPa) with access to normoxic air, the knifefish achieved a U-crit of 2.0 +/- 0.1. BL. s(-1) and an AMR of 338 +/- 29. mg. kg(-1). h(-1), similar to aquatic normoxia, but with 55 +/- 5% of AMR derived from air breathing. Indeed, f(AB) was higher than in normoxia at all swimming speeds, with a profound exponential increase during exercise. If the knifefish were denied access to air in hypoxia, U-crit declined to 1.2 +/- 0.1. BL. s(-1) and AMR declined to 199 +/- 29. mg. kg(-1). h(-1). Therefore, air breathing allowed the knifefish to avoid limitations to aerobic scope and exercise performance in aquatic hypoxia.
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Langue English Langue du Résumé Titre Original
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ISSN 0022-0949 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 904
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