| Effects of feeding and hypoxia on cardiac performance and gastrointestinal blood flow during critical speed swimming in the sea bass Dicentrarchus labrax. | |
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MedLine Citation:
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PMID: 19559805 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Previous studies have shown that if European sea bass are exercised after feeding, they can achieve a significantly higher maximum metabolic rate (MMR) than when fasted. They can meet combined metabolic demands of digestion (specific dynamic action, SDA) and maximal aerobic exercise, with no decline in swimming performance. If, however, exposed to mild hypoxia (50% saturation), bass no longer achieve higher MMR after feeding but they swim as well fed as fasted, due to an apparent ability to defer the SDA response. This study explored patterns of cardiac output (Q(A)) and blood flow to the gastrointestinal tract (Q(GI)) associated with the higher MMR after feeding, and with the ability to prioritise swimming in hypoxia. Sea bass (mean mass approximately 325 g, forklength approximately 27 cm) were instrumented with flow probes to measure Q(A) and Q(GI) during an incremental critical swimming speed (U(crit)) protocol in a tunnel respirometer, to compare each animal either fasted or 6h after a meal of fish fillet equal to 3% body mass. Feeding raised oxygen uptake (M(O2)) prior to exercise, an SDA response associated with increased Q(A) (+30%) and Q(GI) (+100%) compared to fasted values. As expected, when exercised the fed bass maintained the SDA load throughout the protocol and achieved 14% higher MMR than when fasted, and the same U(crit) (approximately 100 cm s(-1)). Both fed and fasted bass showed pronounced increases in Q(A) and decreases in Q(GI) during exercise and the higher MMR of fed bass was not associated with higher maximum Q(A) relative to when fasted, or to any differences in Q(GI) at maximum Q(A). In hypoxia prior to exercise, metabolic and cardiac responses to feeding were similar compared to normoxia. Hypoxia caused an almost 60% reduction to MMR and 30% reduction to U(crit), but neither of these traits differed between fed or fasted bass. Despite hypoxic limitations to MMR and U(crit), maximum Q(A) and patterns of Q(GI) during exercise in fasted and fed bass were similar to normoxia. Estimating GI oxygen supply from Q(GI) indicated that the ability of bass to prioritise aerobic exercise over SDA when metabolically limited by hypoxia was linked to an ability to defer elements of the SDA response occurring outside the GI tract. |
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Authors:
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A Dupont-Prinet; G Claireaux; D J McKenzie |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2009-06-25 |
Journal Detail:
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Title: Comparative biochemistry and physiology. Part A, Molecular & integrative physiology Volume: 154 ISSN: 1531-4332 ISO Abbreviation: Comp. Biochem. Physiol., Part A Mol. Integr. Physiol. Publication Date: 2009 Oct |
Date Detail:
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Created Date: 2009-07-28 Completed Date: 2009-08-28 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 9806096 Medline TA: Comp Biochem Physiol A Mol Integr Physiol Country: United States |
Other Details:
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Languages: eng Pagination: 233-40 Citation Subset: IM |
Affiliation:
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Université Montpellier 2, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France. aurelie.prinet@laposte.net |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Bass / physiology* Cardiac Output / physiology Dietary Proteins / administration & dosage Digestion / physiology Eating / physiology Energy Metabolism / physiology* Female Food Deprivation / physiology Gastrointestinal Tract / blood supply* Heart Rate / physiology Hemodynamics / physiology* Male Oxygen / physiology* Oxygen Consumption / physiology Physical Exertion / physiology* Regional Blood Flow Stroke Volume / physiology Swimming / physiology |
| Chemical | |
Reg. No./Substance:
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0/Dietary Proteins; 7782-44-7/Oxygen |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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