魚類のアミラーゼ, α-およびβ-グルコシダーゼ, β-ガラクトシダーゼの分布

Abstract

The activities of amylase, α- and β-glucosidase, and β-galactosidase in the tissues of carp, Cyprinus carpio, crucian carp, Carassius carassius, grass carp, Ctenopharyngodon idellus, rainbow trout, Salmo gairdnerii, silver carp, Hypophthalmichthys molitrix, tilapia, Tilapia nilotica, and yellowtail, Seriola quinqueradiata, were investigated to see the relation between the feeding habits and the distribution of the enzymes. The species exhibiting the strongest amylase activity of the digestive tracts is crucian carp followed by grass carp, tilapia, carp, and silver carp. Very weak or negligible activities of amylase are found in the digestive tracts of rainbow trout, eel, and yellowtail. These results may support the concept that the amylase activity of the digestive tracts depends on the feeding habit of fish. The liver and spleen of the herbivorous and the omnivorous also show the strong amylase activities, while the carnivorous does not. The activities of α-glucosidase in the tissues of grass carp, the herbivorous, are much stronger than those of eel, the carnivorous. On the other hand, the apparent correlation between the feeding habits and the activities of β-glucosidase is not found even with the digestive tracts. The activities of β-galactosidase in the digestive tracts are stronger in the herbivorous and the omnivorous (except the carp) than in the carnivorous. The liver, kidney, and spleen have also the high activities of β-galactosidase. The intracellular distribution of β-galactosidase in the tissues of fish were confirmed by the histochemical investigations.