[Characterization of the intestinal digestive glycosidases in plankton- and benthos-feeding species of the fish genus Ballerus (Cyprinidae)].

The activity of hydrolases (maltase, saccharase, amylolytic activity) in the intestinal mucosa of the plankton-feeding zope Ballerus ballerus and the benthos-feeding white-eye bream Ballerus sapa was investigated. The temperature characteristics of maltase hydrolysis (T(opt) and E(act)) are similar in both species. The lower K(m) of maltase hydrolysis in the white-eye bream reflects a higher enzyme/substrate affinity and indicates a more effective carbohydrate hydrolysis in the benthos-versus plankton-feeding species. The glycosidase activity in the white-eye bream is twice as high as in the zope. This may be due not only to different feeding spectra and biochemical food contents but also to the differences in thyroid status of species under consideration.