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Differential freshwater adaptation in juvenile sea-bass Dicentrarchus labrax: involvement of gills and urinary system.
J Exp Biol. 2005 Oct; 208(Pt 20):3859-71.JE

Abstract

The effects of long-term freshwater acclimatization were investigated in juvenile sea-bass Dicentrarchus labrax to determine whether all sea-bass juveniles are able to live in freshwater and to investigate the physiological basis of a successful adaptation to freshwater. This study particularly focused on the ability of sea-bass to maintain their hydromineral balance in freshwater and on their ion (re)absorbing abilities through the gills and kidneys. Two different responses were recorded after a long-term freshwater acclimatization. (1) Successfully adapted sea-bass displayed standard behavior; their blood osmolality was maintained almost constant after the freshwater challenge, attesting to their efficient hyperosmoregulation. Their branchial and renal Na+/K+-ATPase abundance and activity were high compared to seawater fish due to a high number of branchial ionocytes and to the involvement of the urinary system in active ion reabsorption, producing hypotonic urine. (2) Sea-bass that had not successfully adapted to freshwater were recognized by abnormal schooling behavior. Their blood osmolality was low (30% lower than in the successfully adapted sea-bass), which is a sign of acute osmoregulatory failure. High branchial Na+/K+-ATPase abundance and activity compared to successfully adapted fish were coupled to a proliferation of gill chloride cells, whose ultrastructure did not display pathological signs. The large surface used by the gill chloride cells might negatively interfere with respiratory gas exchanges. In their urinary system, enzyme abundance and activity were low, in accordance with the observed lower density of the kidney tubules. Urine was isotonic to blood in unsuccessfully adapted fish, ruling out any participation of the kidney in hyperosmoregulation. The kidney failure seems to generate a compensatory ion absorption through increased gill activity, but net ion loss through urine seems higher than ion absorption by the gills, leading to lower hyper-osmoregulatory performance and to death.

Authors+Show Affiliations

Laboratoire Génome, Populations, Interactions, Adaptation, UMR 5171, Université Montpellier II, Place E. Bataillon, 34095 Montpellier, Cedex 05, France. nebelcatherine@yahoo.frNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

16215214

Citation

Nebel, Catherine, et al. "Differential Freshwater Adaptation in Juvenile Sea-bass Dicentrarchus Labrax: Involvement of Gills and Urinary System." The Journal of Experimental Biology, vol. 208, no. Pt 20, 2005, pp. 3859-71.
Nebel C, Romestand B, Nègre-Sadargues G, et al. Differential freshwater adaptation in juvenile sea-bass Dicentrarchus labrax: involvement of gills and urinary system. J Exp Biol. 2005;208(Pt 20):3859-71.
Nebel, C., Romestand, B., Nègre-Sadargues, G., Grousset, E., Aujoulat, F., Bacal, J., Bonhomme, F., & Charmantier, G. (2005). Differential freshwater adaptation in juvenile sea-bass Dicentrarchus labrax: involvement of gills and urinary system. The Journal of Experimental Biology, 208(Pt 20), 3859-71.
Nebel C, et al. Differential Freshwater Adaptation in Juvenile Sea-bass Dicentrarchus Labrax: Involvement of Gills and Urinary System. J Exp Biol. 2005;208(Pt 20):3859-71. PubMed PMID: 16215214.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Differential freshwater adaptation in juvenile sea-bass Dicentrarchus labrax: involvement of gills and urinary system. AU - Nebel,Catherine, AU - Romestand,Bernard, AU - Nègre-Sadargues,Geneviève, AU - Grousset,Evelyse, AU - Aujoulat,Fabien, AU - Bacal,Julien, AU - Bonhomme,François, AU - Charmantier,Guy, PY - 2005/10/11/pubmed PY - 2006/1/13/medline PY - 2005/10/11/entrez SP - 3859 EP - 71 JF - The Journal of experimental biology JO - J. Exp. Biol. VL - 208 IS - Pt 20 N2 - The effects of long-term freshwater acclimatization were investigated in juvenile sea-bass Dicentrarchus labrax to determine whether all sea-bass juveniles are able to live in freshwater and to investigate the physiological basis of a successful adaptation to freshwater. This study particularly focused on the ability of sea-bass to maintain their hydromineral balance in freshwater and on their ion (re)absorbing abilities through the gills and kidneys. Two different responses were recorded after a long-term freshwater acclimatization. (1) Successfully adapted sea-bass displayed standard behavior; their blood osmolality was maintained almost constant after the freshwater challenge, attesting to their efficient hyperosmoregulation. Their branchial and renal Na+/K+-ATPase abundance and activity were high compared to seawater fish due to a high number of branchial ionocytes and to the involvement of the urinary system in active ion reabsorption, producing hypotonic urine. (2) Sea-bass that had not successfully adapted to freshwater were recognized by abnormal schooling behavior. Their blood osmolality was low (30% lower than in the successfully adapted sea-bass), which is a sign of acute osmoregulatory failure. High branchial Na+/K+-ATPase abundance and activity compared to successfully adapted fish were coupled to a proliferation of gill chloride cells, whose ultrastructure did not display pathological signs. The large surface used by the gill chloride cells might negatively interfere with respiratory gas exchanges. In their urinary system, enzyme abundance and activity were low, in accordance with the observed lower density of the kidney tubules. Urine was isotonic to blood in unsuccessfully adapted fish, ruling out any participation of the kidney in hyperosmoregulation. The kidney failure seems to generate a compensatory ion absorption through increased gill activity, but net ion loss through urine seems higher than ion absorption by the gills, leading to lower hyper-osmoregulatory performance and to death. SN - 0022-0949 UR - https://www.unboundmedicine.com/medline/citation/16215214/Differential_freshwater_adaptation_in_juvenile_sea_bass_Dicentrarchus_labrax:_involvement_of_gills_and_urinary_system_ L2 - http://jeb.biologists.org/cgi/pmidlookup?view=long&pmid=16215214 DB - PRIME DP - Unbound Medicine ER -