Plasma ionic regulation and gill Na+/K+-ATPase changes during rapid transfer to sea water of yearling rainbow trout, Salmo gairdneri: time course and seasonal variation

摘要: Danish rainbow trout, Salmo gairdneri Richardson, (40–65 g) were transferred to 28%o sea water at intervals throughout the early spring and summer. Gill Na+/K+-ATPase of fish kept in fresh surged distinctly during May. Simultaneously, a body silvering occurred plasma concentrations Cl−, Na+ total thyroxine (T4) decreased. The seawater transfer-induced adaptive response electrolytes comprised biphasic change, i.e., an adjustive peak phase regulatory lasting for 2 days 1 week after transfer, respectively. Further, gill activity increased new level initial lag 2–3 days, but electrolyte regulation was mostly initiated prior change ATPase activity. In spite increasing pre-transfer freshwater spring, level, degree muscle dehydration mortality from April July. apparent uncoupling is discussed relation smelting prediction hypo-osmoregulatory performance.