Rainbow trout (Salmo gairdneri) were exercised at cruising speeds for 5hours. A slight but significant increase in dorsal aortic blood pH after I hour ofexercise was accompanied by significant decreases in PeDl and total C02content of blood. These changes were maintained throughout the exercise periodof 5 hours. This respiratory alkalosis could be due to hyperventilation and/orthe result of increased uptake of Na+ and Cl- which occurred along with theincrease in plasma volume in order to maintain normal osmotic concentrations.The uptake of Na+ and CI- occurred presumably via branchial Na+ /H+ andCI- /HCO2- ion exchange mechanisms.
Author Biography
M. V. E. ATTYGALLE, Department of Zoology,
University of Sri Jayewardenepura, Nugegoda
