Document Detail

An investigation of metabolic prioritization in the European sea bass, Dicentrarchus labrax.
MedLine Citation:
PMID:  19951229     Owner:  NLM     Status:  MEDLINE    
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.
H?l?ne Jourdan-Pineau; Aur?lie Dupont-Prinet; Guy Claireaux; David J McKenzie
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Physiological and biochemical zoology : PBZ     Volume:  83     ISSN:  1537-5293     ISO Abbreviation:  Physiol. Biochem. Zool.     Publication Date:    2010 Jan-Feb
Date Detail:
Created Date:  2009-12-18     Completed Date:  2010-03-23     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100883369     Medline TA:  Physiol Biochem Zool     Country:  United States    
Other Details:
Languages:  eng     Pagination:  68-77     Citation Subset:  IM    
Centre d'Ecologie Fonctionnelle et Evolutive (Unit? Mixte de Recherche [UMR] 5171 Centre National de la Recherche Scientifique [CNRS]), 34293 Montpellier Cedex 5, France.
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MeSH Terms
Anoxia / metabolism
Basal Metabolism / physiology
Bass / metabolism*
Energy Metabolism / physiology
Oxygen / metabolism*
Oxygen Consumption / physiology
Physical Conditioning, Animal / physiology
Regression Analysis
Swimming / physiology
Reg. No./Substance:

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