Effect of purified microcystin on oxidative stress of silver carp Hypophthalmichthys molitrix larvae under different ammonia concentrations

► Significant oxidative stress responses of silver carp larvae to NH3-N and MC-LR occurred. ► Significant interaction was detected between NH3-N and MC-LR on GSH and MDA. ► Changes in SOD and GSH are time or dose-dependent on NH3-N and MC-LR exposure. ► GSH, SOD, and MDA are good biomarkers of oxidative stress.