Separate and Joint Effects of Copper and Zinc on the Intestine Carbohydrase Activity in vitro in Freshwater Teleosts

摘要

The separate and joint effect of Cu~(2+) and Zn~(2+) of 0.1-25 mg 1~(-1) concentrations on the intestine carbohydrase activity were studied in vitro in 11 freshwater bone fishes. The total amylolytic activity of the fish intestinal mucosa decreased simultaneously with an increase in the Cu and Zn concentration. The maximal inhibitory effect varied from 15 to 46% and depended on the fish species. Copper had a more toxic effect on the amylolytic enzymes than zinc in planktivorous and bottom-feeding fish; the opposite pattern was observed in typical and facultative ichthyophagous species. The sucrase activity also decreased in the presence of Cu~(2+) and Zn~(2+), with minor exceptions; at the same time it increased by 18-50% in bream, ide, and burbot in the presence of Zn. The joint effect of Cu~(2+) and Zn~(2+) (1 :1) on the intestinal carbohydrase hydrolysis activity was significantly lower than when they were separate.