Elena Ciornea


STUDIES ON THE ACTIVITY OF SOME PEPTID-HYDROLASES AT SILVER CARP, BIGHEAD CARP AND GRASS CARP

Elena Ciornea, Gabriela Dumitru

Abstract
The digestion is a biochemical and mechanical complex process which takes place at digestive tube level, by way of which the ingested brute nourishment are transformed in substances more simple, easily to absorb. Within our study weíve proposed to determinate the activity of pepsin and trypsin from the medium intestineís level at five representatives belonging to Hypophthalmichthys molitrix (silver carp), Aristichthys nobilis (bighead carp) and Ctenopharyngodon idella (grass carp) of two summer-old. The proteinasic activity was evaluated through the dosage of hydrolysis products of substratum under the action of these enzymes (hemoglobin for pepsin and casein in the case of trypsin) with the help of Folin-Ciocalteu reactive through colorimetric method. The analysis of obtained results underlines, on the one hand, major differences in what concerns the activity of the two enzymes implicated in the proteins metabolism, the medium value of pepsinís activity being, in general, more inferior comparatively with the trypsinís level activity at all three culture cyprinid species taken into study, and on the other hand exist differences between species, the grass carp presenting an activity more diminishing in the case of both peptid-hydrolases.

Key words: pepsin, trypsin, culture cyprinids