Effect of cyanobacteria on immune function of crucian carp (Carassius auratus) via chronic exposure in diet

► Fish was exposed to microcystins via dietary inclusion of cyanobacteria. ► Hyperemic tissues and apoptosis in lymphocyte of head kidney, spleen were detected. ► Lysozyme activity increase in low dose group but decrease in high dose group. ► Macrophage bactericidal activity increase in low dose group.