TROUT PLASMA METABOLITES, BLOOD FACTORS AND SPLEEN CONTRACTION - RESPONSES TO EXERCISE

Fish react to handling and capture with a burst of exercise that affec ts them deeply. The present study examines the effect of such severe e xercise and the time course of recovery on the hematology (including s pleen response) and metabolism of a population of cultured rainbow tro ut. Exercise was induced by continuous chasing for 5 min when the trou t showed signs of exhaustion. Such exercise led to spleen contraction and an increase in haematocrit values. Carbohydrates were mobilized an d anaerobic glycolysis produced lactate without significant effect on lipid metabolism. The conclusion is reached that the respiratory prope rties of rainbow trout blood do not change following severe exercise, while muscle anaerobic metabolism is slightly activated as deduced fro m the fast and short lactacidemia observed, which may have been relate d to a reduced stressing component, as the exercise was performed in t he same environment in which the fish were reared.