Changes in amount of glycogen and lipid in hepatopancreas and of blood glucose of carp under starvation and by feeding the diets in different composition consisting of car-bohydrate and protein were investigated as the first step to study the utilization form of energy in carp.
Under starvation the consumption of lipid prior to glycogen in hepatodancreas and temporary increase of the blood glucose level were found at the same time. In breeding experiments, as the carbohydrate content in diet increased or protein decreased, glycogen in hepatopancreas increased while lipid in hepatopancreas and blood glucose level decreased.
From these results it was suggested in carp unlike in mammals that carbohydrate is hardly converted to lipid but that protein is principally converted to lipid; carbohydrate does not precede either protein or lipid as energy source, but a certain amount of it is neccessary.