Response of digestive enzyme activities to waterborne copper exposure and recovery in Carassius auratus gibelio var

This study aimed to assess the effect of waterborne copper on the digestive enzyme activities of the freshwater fish Carassius auratus gibelio var, and to assess the reversibility of these digestive enzyme activities. Carassius auratus gibelio var were exposed to different concentrations (0.05, 0.10, 0.20, 0.50, and 1.00 mg/L) of copper for 96 h. Subsequently, the 1.00 mg/L exposure group was transferred to clean water for different days (1, 5, 15, and 30 d) to assess the recovery profile. The responses of protease, amylase, and lipase activities in hepatopancreas, foregut, midgut, and hindgut to copper exposure and recovery were investigated. Results showed that after 96 h of copper exposure, the digestive enzyme activities in different organs varied. After removing the 1.00 mg/L copper stress, all digestive enzyme activities normalized within 30 days. The protease activity in the hepatopancreas of Carassius auratus gibelio var was more sensitive to copper stress and may be used as a suitable biomarker for copper contamination in an aquatic environment.