Enzymatic profiles (osidases) of two cyprinids: Ctenopharyngodon idella and Carassius auratus

Cellulasic activity being very low in grass carp, Ctenopharyngodon idella (herbivorous cyprinid), and goldfish, Carassius auratus (omnivorous cyprinid), we undertook a study of the osidasic profile in the digestive tract of these species held in the same tank at 20°C and at 28°C. Osidase API-ZYM plates allowing the study of the last stages of the lysis of polyosides — but not that of the complex glucides—were used. The results showed no significant temperature effect on overall enzyme production. However, such an effect did exist for certain enzymes (β-D-glucosidase and β-maltosidase in goldfish). The two fish species do not provide the same enzymes with the same abundance: α-D-galactosidase, β-D-galactosidase, phospho-β-D-galactosidase and α-L-arabinosidase prevailing in the grass carp while β-D-glucosidase, β-maltosidase and α-L-fucosidase prevail in the goldfish. There is an overall activity correlation between most of the enzymes. Thus, the enzymatic profiles of the two species can be partly differentiated, indicating different capacities to metabolize even slightly complex glucids.