ハマチとコイの糖代謝の比較

抄録

In order to clarify the differences in carbohydrate metabolism of yellowtail (Seriola quinqueradiata) and carp (Cyprinus carpio), activities of digestive enzymes and carbohydrate-metabolizing enzymes, digestibilities of dietary starch and protein, and the glucose tolerande were determined. In the case of yellowtail, the apparent digestibilities of dietary starch and protein became lower with the increase of starch content in the diet. However, these digestibilities were almost constant in carp regardless of the starch content. Compared with carp, yellowtail possessed hith activities of gluconeogenic enzymes and pepsin, and low activities of glycolytic enzymes, pentose cycle dehydrogenases and amylase. The blood glucose levels of both fishes increased markedly during the first 1-2 hours after oral administration of glucose, then decreased to the original level after 4-7 hours. However, more pronounced and prolonged hyperglycemia was observed in yellowtail. These results suggest that yellowtail possesses a high capacity for gluconeogenesis and a low ability to digest and utilize dietary carbohydrate.