Hyper-osmoregulatory capacity of the Chinese mitten crab (Eriocheir sinensis) exposed to cadmium; acclimation during chronic exposure.
The aim of this study was to evaluate the effects of waterborne cadmium on hyper-osmoregulatory capacity of the Chinese mitten crab Eriocheir sinensis acclimated to freshwater. For this purpose, crabs were submitted to acute (0.5 mg Cd L(-1) for 1, 2 or 3 days), chronic (10 or 50 microg Cd L(-1) for 30 days) or chronic, immediately followed by acute, exposure. While no effect was observed after 1 or 2 days, hemolymph osmolality, Na(+) and Cl(-) concentrations were significantly reduced after 3 days of acute exposure. Under this latter condition, the respiratory anterior gill ultrastructure, Na(+)/K(+)-ATPase and cytochrome c oxidase activities were significantly impaired. In contrast, the osmoregulatory posterior gill was unaffected for all treatments. As a consequence, we suggest that the observed hyper-osmoregulatory capacity impairment is the result of increased dissipative flow of ions and/or water through anterior gills. In contrast to acute exposure, chronic exposure did not induce any observable effect. However, crabs submitted to a known deleterious acute condition (0.5 mg Cd L(-1) for 3 days) directly after chronic exposure to 50 microg Cd L(-1) for 30 days showed normal hyper-osmoregulatory capacity with no change in gill Na(+)/K(+)-ATPase activity, and only little disturbance of anterior gill ultrastructure. These results demonstrate that a chronic cadmium exposure can induce acclimation mechanisms related to osmoregulation in this euryhaline decapod crustacean.
Silvestre
F
F
Unité de Recherche en Biologie des Organismes, Facultés Universitaires Notre-Dame de la Paix, Namur, Belgium. frederic.silvestre@fundp.ac.be
Trausch
G
G
Devos
P
P
D000064:Acclimatization / Q000187:drug effects* / Q000502:physiology; D000818:Animals; D003386:Brachyura / Q000187:drug effects* / Q000502:physiology / Q000648:ultrastructure; D002104:Cadmium / Q000008:administration & dosage*; D004334:Drug Administration Schedule; D008297:Male; D014882:Water-Electrolyte Balance / Q000187:drug effects* / Q000502:physiology
D002104:Cadmium