RATE OF GASTRIC EVACUATION IN BROWN TROUT (SALMO-TRUTTA L) IN ACIDIFIED AND NON-ACIDIFIED WATER

Gastric evacuation rate in brown trout (Salmo trutta L.) was studied in water qualities characteristic of non-acidified and acidified waters. The level of plasma chloride was reduced and hematocrit increased in the group exposed to acid water. The gastric evacuation rate was described by an exponential function. Instantaneous rates of gastric evacuation were not significantly different between the two groups. In both of the groups the rates were lower than observed in corresponding studies of brown trout. This was most likely caused by handling stress during the experiment.