Effect of a Partial Loss of Scales and Mucous on Carbohydrate Metabolism in Rainbow Trout (Salmo gairdneri)

Abstract

This study was undertaken to determine what part partial scaling and partial desliming might play in the survival of trout. Carbohydrate metabolism in these trout was studied and in addition, hemoglobin levels and red cell volumes were studied to serve as indicators of osmotic shifts of water.Increases in lactate were minimal and occurred during the first few hours of holding after the removal of [Formula: see text] to [Formula: see text] of the scales. There were slight changes in hemoglobin levels and red cell volumes which appeared to coincide with activity as reflected by lactate levels. There was a three- to fourfold increase in the blood glucose level of partially scaled fish. Liver glycogen levels dropped to [Formula: see text] of the air-dipped control value for fish that had been [Formula: see text] scaled and held in holding baskets for a period of 140 hr. Only one mortality occurred in all the experiments.The following conclusions were reached. Partial loss of scales or mucous does not result in the death of rainbow trout (Salmo gairdneri). Partial scaling or desliming of the fish was accompanied by a significant increase in blood glucose (p < 0.05).