16.P15. Branchial osmoregulatory response to salinity challenge in the Lusitanian toadfish
Halobatrachus didactylus, a marine teleost found in coastal lagoons and river estuaries is often exposed to important salinity changes. Despite its aglomerular kidney, it is able to survive in hypo-osmotic environments, likely via compensatory actions from gills and intestine. We aimed at evaluating...
| Autores: | , , , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2007 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/326203 |
| Acceso en línea: | http://hdl.handle.net/10261/326203 |
| Access Level: | acceso abierto |
| Palabra clave: | Pesquerías Centro Oceanográfico de Málaga |
| Sumario: | Halobatrachus didactylus, a marine teleost found in coastal lagoons and river estuaries is often exposed to important salinity changes. Despite its aglomerular kidney, it is able to survive in hypo-osmotic environments, likely via compensatory actions from gills and intestine. We aimed at evaluating the response of the branchial tissue of H. didactylus to salinity changes. Fish allocated into 15 groups were exposed to different salinities (0, 5, 12, 36 and 55 ppt) for 4, 24 and 96 h. At each time point, blood samples were taken and osmolality, glucose and ion concentration determined. Fish were sacrificed and gill samples collected for measurement of Na+/K+-ATPase activity and fixed for histology and immunohistochemistry. Mortality occurred only in the 0 ppt group, in which all fish died within 48 to 96 h. Blood osmolality was significantly conditioned by environmental salinity, increasing at 55 ppt and dropping at 5 and 0 ppt. At 4 h, glucose levels were higher in fish in altered salinity than in those in the 100% seawater group, possibly an indication of the adaptive effort required. Adjustments in Na+/K+-ATPase activity were seen at 24 and 96 h after transfer, in a characteristic u-shape, peaking at extreme low and high salinities. Contrary to most teleosts, the chloride cells in H. didactylus are located in the secondary lamellae and not in the primary filament. Salinity acclimation did not change cell distribution. H. didactylus are capable of swift and significant branchial adjustments to ambient salinity and further studies are needed to evaluate the role of kidney and intestine in the osmoregulatory response. |
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