Alterations in Glycogen, Glucose and Lactate in Rainbow and Kamloops Trout, Salmo gairdneri, Following Muscular Activity

Abstract

Rainbow trout [Formula: see text] years old (fall spawners) raised in the hatchery at Summerland, B.C., and 2-year-old mature spawning Kamloops trout (spring spawners) captured from Lake Okanagan, were subjected to 15 minutes strenuous exercise. Muscle glycogen was depleted in both groups. Following 30 minutes of moderate activity, muscle glycogen remained high in the [Formula: see text]-year-old trout. Liver glycogen levels were not significantly lowered during either strenuous or moderate exercise. Blood lactate levels were markedly elevated during 15 min of strenuous exercise and continued to rise for 2 hours of post-exercise recovery in both groups of fish. In the [Formula: see text]-year-old trout, blood lactate declined to resting levels at about the 8th hour of recovery, and was increased 3-fold following 30 min of moderate activity. Blood glucose and hemoglobin were not significantly altered during either strenuous or moderate activity.In the [Formula: see text]-year-old trout, starvation of up to 7 days duration resulted in a marked depletion of liver glycogen. There was little change in muscle glycogen, blood lactate, glucose or hemoglobin, regardless of whether or not the fish had been exercised at the beginning of the starvation period. Feeding during the period of recovery from 15 min of strenuous exercise resulted in increases in both muscle and liver glycogen levels.