title: Exposure to chronic moderate hypoxia impacts physiological and developmental traits of European sea bass (Dicentrarchus labrax) larvae.
abstract: Since European sea bass (Dicentrarchus labrax) larvae occurred in coastal and estuarine waters at early life stages, they are likely to be exposed to reduced dissolved oxygen waters at a sensitive developmental stage. However, the effects of hypoxia at larval stage, which depend in part on fish species, remain very poorly documented in European sea bass. In the present study, the impacts of an experimental exposure to a chronic moderate hypoxia (40 % air saturation) between 30 and 38 days post-hatching on the physiological and developmental traits of European sea bass larvae were assessed. This study was based on the investigation of survival and growth rates, parameters related to energy metabolism [Citrate Synthase (CS) and Cytochrome-c Oxidase (COX) activities], and biological indicators of the maturation of digestive function [pancreatic (trypsin, amylase) and intestinal (Alkaline Phosphatase "AP" and Aminopeptidase-N "N-LAP") enzymes activities]. While condition of hypoxia exposure did not induce any significant mortality event, lower growth rate as well as CS/COX activity ratio was observed in the Hypoxia Treatment group. In parallel, intestinal enzyme activities were also lower under hypoxia. Altogether, the present data suggest that sea bass larvae cope with moderate hypoxia by (1) reducing processes that are costly in energy and (2) regulating mitochondria functions in order to respond to energy-demand conditions. Both these effects are associated with a delay in the maturation of the digestive function.
authors.affiliation: Ifremer, LEMAR UMR 6539 CNRS-UBO-IRD-Ifremer, ZI de la Pointe du Diable, CS 10070, 29280, Plouzané, France.
authors.forename: Gwenaëlle
authors.initials: G
authors.lastname: Vanderplancke
authors.forename: Guy
authors.initials: G
authors.lastname: Claireaux
authors.forename: Patrick
authors.initials: P
authors.lastname: Quazuguel
authors.forename: Christine
authors.initials: C
authors.lastname: Huelvan
authors.forename: Charlotte
authors.initials: C
authors.lastname: Corporeau
authors.forename: David
authors.initials: D
authors.lastname: Mazurais
authors.forename: José-Luis
authors.initials: JL
authors.lastname: Zambonino-Infante
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000626:Aminopeptidases / Q000378:metabolism; D000681:Amylases / Q000378:metabolism; D000704:Analysis of Variance; D000818:Animals; D001492:Bass / Q000502:physiology*; D003576:Electron Transport Complex IV / Q000378:metabolism; D004734:Energy Metabolism / Q000502:physiology*; D005393:Fish Diseases / Q000503:physiopathology*; D000860:Hypoxia / Q000503:physiopathology / Q000662:veterinary*; D007814:Larva / Q000254:growth & development; D008928:Mitochondria / Q000378:metabolism*; D016019:Survival Analysis; D014357:Trypsin / Q000378:metabolism
chemical_list: D003576:Electron Transport Complex IV; D000469:Alkaline Phosphatase; D000681:Amylases; D000626:Aminopeptidases; D014357:Trypsin