title: Salinity effects on osmoregulation and gill morphology in juvenile Persian sturgeon (Acipenser persicus).
abstract: The effect of abrupt and 5-day gradual salinity transfers from freshwater (FW) to 11 ‰ Caspian Sea brackish water (BW) was investigated in juvenile Persian sturgeon Acipenser persicus with three different weight groups: 1-2 g (1.62 ± 0.27 g), 2-3 g (2.55 ± 0.41 g) and 3-5 g (4.28 ± 0.76 g). Mortality rates, blood osmotic pressure, gill morphology and branchial Na+, K+-ATPase (NKA) activity were measured 4 and 10 days after abrupt transfer and 9 and 15 days after the initial gradual transfer (i.e. 4 and 10 days after reaching Caspian Sea salinity). Fish under 3 g could not survive increased salinity, and the blood osmotic pressure of the remaining surviving fish increased and remained elevated. However, heavier fish were able to survive and successfully acclimate, even to rapid salinity change with osmotic pressure reduced to Caspian Sea osmolality levels. At the gill level, the developmental increase in chloride cell volume and a higher NKA content most probably allow juveniles weighing more than 2 g to sharply increase NKA activity if the fish are transferred to BW. The rapid chloride cell proliferation occurring with increased salinity should strengthen this acclimation response. Therefore, a drastic physiological change occurs when fish weigh more than 2 g that allows migration to higher salinities. The triggering signal on chloride cells must be further investigated in order to optimize this functional step.
authors.affiliation: Faculty of Marine Sciences, Tarbiat Modares University, P.O. Box 46414-356, Noor, Iran.|UMR MARBEC, MARBEC (IRD - Ifremer - Univ. Montpellier - CNRS), University of Montpellier, Place Eugène Bataillon, 34095, Montpellier Cedex 5, France.
authors.forename: Seyedeh Ainaz
authors.initials: SA
authors.lastname: Shirangi
authors.affiliation: Faculty of Marine Sciences, Tarbiat Modares University, P.O. Box 46414-356, Noor, Iran. kalbassi_m@modares.ac.ir.
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Kalbassi
authors.affiliation: Faculty of Marine Sciences, Tarbiat Modares University, P.O. Box 46414-356, Noor, Iran.
authors.forename: Saber
authors.initials: S
authors.lastname: Khodabandeh
authors.affiliation: Faculty of Agriculture and Natural Resources, Gonbad Kavous University, Gonbad, Iran.
authors.forename: Hojatollah
authors.initials: H
authors.lastname: Jafarian
authors.affiliation: UMR MARBEC, MARBEC (IRD - Ifremer - Univ. Montpellier - CNRS), University of Montpellier, Place Eugène Bataillon, 34095, Montpellier Cedex 5, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Lorin-Nebel
authors.affiliation: UMR MARBEC, MARBEC (IRD - Ifremer - Univ. Montpellier - CNRS), University of Montpellier, Place Eugène Bataillon, 34095, Montpellier Cedex 5, France.
authors.forename: Emilie
authors.initials: E
authors.lastname: Farcy
authors.affiliation: UMR MARBEC, MARBEC (IRD - Ifremer - Univ. Montpellier - CNRS), University of Montpellier, Place Eugène Bataillon, 34095, Montpellier Cedex 5, France. jehan-herve.lignot@univ-montp2.fr.
authors.forename: Jehan-Hervé
authors.initials: JH
authors.lastname: Lignot
mesh_terms: D000818:Animals; D049628:Body Size; D005399:Fishes / Q000033:anatomy & histology / Q000097:blood / Q000254:growth & development / Q000378:metabolism; D005880:Gills / Q000033:anatomy & histology / Q000378:metabolism / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D064587:Osmoregulation; D054712:Salinity; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
chemical_list: D000254:Sodium-Potassium-Exchanging ATPase
keywords: Chloride cell; Juvenile; Na+, K+-ATPase activity; Osmoregulation; Persian sturgeon; Salinity acclimation