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Auteur Alix, M.; Blondeau-Bidet, E.; Grousset, E.; Shiranghi, A.; Vergnet, A.; Guinand, B.; Chatain, B.; Boulo, V.; Lignot, J.-H. doi  openurl
  Titre Effects of fasting and re-alimentation on gill and intestinal morphology and indicators of osmoregulatory capacity in genetically selected sea bass (Dicentrarchus labrax) populations with contrasting tolerance to fasting Type Article scientifique
  Année 2017 Publication Revue Abrégée Aquaculture  
  Volume 468 Numéro Pages 314-325  
  Mots-Clés bream sparus-auratus; dietary-sodium chloride; Enterocyte; Fasting; feed deprivation; fish; fresh-water; fundulus-heteroclitus; Gill ionocyte; Morphometry; Ontogeny; oreochromis-mossambicus; Osmoregulation; rainbow-trout; Re-alimentation; Salinity; Sea bass  
  Résumé Fasting and refeeding occur naturally in predators but this is largely ignored when dealing with farmed fish. Therefore,the effects of 3-week fasting and re-alimentation (2.5% of the individual body mass) were investigated using two genetically selected populations (F2 generation) of 250 g juvenile sea bass (Dicentrarchus labrax L.). Blood osmolarity, gill and intestinal morphology and expression of the sodium pump (Na+, K+-ATPase, NKA) were studied on two phenotypes showing different degrees of body mass loss during food deprivation: one group losing body mass rapidly during fasting (F+) and the other one limiting body mass loss during the same period (F-). Blood osmotic pressure significantly decreases due to re-alimentation in both groups, but this is compensated in the F+ group. In this group, gill ionocytes are smaller and less numerous, but a significantly higher NKA gene expression is noted in the gills in comparison to the F- individuals 48 and 72 h after re-alimentation, and also in the posterior intestine 72 h after re-alimentation. This most probably occurs to compensate for a higher salt intake during nutrient absorption in comparison to the F- group. Furthermore, refed F- fish absorb more lipids along the proximal anterior intestine, and take longer to digest than the F+ group, and show enterocyte vacuolization in the posterior intestine. Therefore, the two selected populations have different postprandial digestive strategies: the F- fish optimize feed efficiency first at the cost of optimal hydromineral adjustment, while the F+ group invests in osmoregulatory performance at the expense of digestive physiology. Statement of relevance: Our paper is highly relevant to the general field of commercial aquaculture. There is an increasing number of research articles dealing with fasting and refeeding in commercial fish and how to improve fish nutrition based oh these physiological data and genetic selection. (C) 2016 Elsevier B.V. All rights reserved.  
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  Editeur Lieu de Publication Éditeur  
  Langue English Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 0044-8486 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 1712  
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Auteur Masroor, W.; Farcy, E.; Gros, R.; Lorin-Nebel, C. doi  openurl
  Titre Effect of combined stress (salinity and temperature) in European sea bass Dicentrarchus labrax osmoregulatory processes Type Article scientifique
  Année 2018 Publication Revue Abrégée Comp. Biochem. Physiol. A-Mol. Integr. Physiol.  
  Volume 215 Numéro Pages 45-54  
  Mots-Clés Osmoregulation; fresh-water; Teleost; goldfish carassius-auratus; Ionocytes; branchial na+/k+-atpase; fish gills; gill morphology; Gill plasticity; Hydromineral balance; k+-atpase activity; mitochondria-rich cells; mozambique tilapia; NKA activity; salmon salmo-salar; Thermal acclimation; tilapia oreochromis-mossambicus  
  Résumé European sea bass Dicentrarchus Iabrax undertake seasonal migrations to estuaries and lagoons that are characterized by fluctuations in environmental conditions. Their ability to cope with these unstable habitats is undeniable, but it is still not clear how and to what extent salinity acclimation mechanisms are affected at temperatures higher than in the sea. In this study, juvenile sea bass were pre-acclimated to seawater (SW) at 18 degrees C (temperate) or 24 degrees C (warm) for 2 weeks and then transferred to fresh water (FW) or SW at the respective temperature. Transfer to FW for two weeks resulted in decreased blood osmolalities and plasma Cl- at both temperatures. In FW warm conditions, plasma Na+ was similar to 15% lower and Cl- was similar to 32% higher than in the temperate-water group. Branchial Na+/K+-ATPase (NKA) activity measured at the acclimation temperature (V-apparent) did not change according to the conditions. Branchial Na+/K+-ATPase activity measured at 37 degrees C (V-max) was lower in warm conditions and increased in FW compared to SW conditions whatever the considered temperature. Mitochondrion-rich cell (MRC) density increased in FW, notably due to the appearance of lamellar MRCs, but this increase was less pronounced in warm conditions where MRC's size was lower. In SW warm conditions, pavement cell apical microridges are less developed than in other conditions. Overall gill morphometrical parameters (filament thickness, lamellar length and width) differ between fish that have been pre acclimated to different temperatures. This study shows that a thermal change affects gill plasticity affecting whole-organism ion balance two weeks after salinity transfer.  
  Adresse  
  Auteur institutionnel Thèse  
  Editeur Lieu de Publication Éditeur  
  Langue English Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 1095-6433 ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel MARBEC @ alain.herve @ collection 2260  
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