title: Adaptive branchial mechanisms in the sturgeon Acipenser naccarii during acclimation to saltwater.
abstract: Variations of Na(+)/K(+)-ATPase activity and fatty-acid composition in the gills of the sturgeon Acipenser naccarii subjected to progressive acclimation to full seawater (35 ppt) were determined in relation to the hypo-osmoregulatory capacity of this species in the hyperosmotic medium. Blood samples were taken and gills arches were removed at intermediate salinity levels between 0 and 35 ppt and after 20 days at constant salinity (35 ppt). Plasma osmolality and Na(+)/K(+)-ATPase activity increased significantly with growing environmental salinity. Total saturated fatty acids (SFAs) decreased, while total polyunsaturated fatty acids (PUFAs) increased significantly with increasing salinity due mainly to changes in n-3 PUFAs (20:5n-3 and 22:6n-3). The n-3/n-6 ratio increased significantly during the acclimation process. The results show a direct relationship between salinity, increased gill Na(+)/K(+)-ATPase activity and ultrastructural changes of the gill chloride cells. Changes in the fatty-acid composition in gills of A. naccarii during progressive acclimation to full seawater suggest that variations of gill fatty acids may also have a role in osmoregulatory mechanisms.
authors.affiliation: Dpt. de Biología Animal y Ecología, Facultad de Ciencias, Universidad de Granada, Spain.
authors.forename: Rosa M
authors.initials: RM
authors.lastname: Martínez-Alvarez
authors.forename: Ana
authors.initials: A
authors.lastname: Sanz
authors.forename: Manuel
authors.initials: M
authors.lastname: García-Gallego
authors.forename: Alberto
authors.initials: A
authors.lastname: Domezain
authors.forename: Julio
authors.initials: J
authors.lastname: Domezain
authors.forename: Ramón
authors.initials: R
authors.lastname: Carmona
authors.forename: M
authors.initials: M
authors.lastname: del Valle Ostos-Garrido
authors.forename: Amalia E
authors.initials: AE
authors.lastname: Morales
mesh_terms: D000064:Acclimatization / Q000502:physiology*; D000818:Animals; D005227:Fatty Acids / Q000378:metabolism; D005399:Fishes / Q000097:blood / Q000502:physiology*; D005618:Fresh Water; D005880:Gills / Q000502:physiology* / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D009994:Osmolar Concentration; D012623:Seawater; D000254:Sodium-Potassium-Exchanging ATPase / Q000502:physiology*; D014882:Water-Electrolyte Balance / Q000502:physiology*
chemical_list: D005227:Fatty Acids; D000254:Sodium-Potassium-Exchanging ATPase