Effects of melatonin feed on histology and antioxidant ability of the gills and oxygen consumption of Chinese mitten crab (Eriocheir sinensis), exposed to acute hypoxia stress

The Chinese mitten crab (Eriocheir sinensis), as a benthic animal, adequate oxygen is very important for their life activities. This study was designed to evaluate the damage of the gill structure and function of E. sinensis under acute hypoxia (DO = 0.5 mgO2L−1,4 h) and the anti-injury effects of melatonin (MT). Histological examination showed predominantly regressive changes in the gills of crab exposed to hypoxia. The histoarchitecture of gills in the hypoxia group showed disrupted pillar cells (PC), the accumulation of hemocytes (HeM) in the hemocoelic space, lifting of lamellar epithelium and the appearance of bigger size of distal tips. Whereas, no such changes were found in MT group. Compared with the Control+hypoxia (C_hyp) group, the MDA of MT + hypoxia (MT_hyp) was significantly decreased (p