Oxidative stress responses in gills of white shrimp Litopenaeus vannamei Boone, 1931 following exposure to cadmium at different salinities

The present study investigated the effects of sublethal concentrations of cadmium (Cd) at different salinity level on the levels of catalase (CAT), glutathione (GSH) and malondialdehyde (MDA) in gills of white shrimp Litopenaeus vannamei. The levels of CAT in gills were significantly higher at salinity 5 than at 15 and 27 with and without Cd exposure. At salinities 5 and 27, the levels of CAT in control gills were significantly higher than in Cd-exposed gills. The levels of GSH in both control and Cd-exposed gills at all salinities were not significantly different. The level of MDA in Cd-exposed gills at salinity 5 was higher than in control gills. Meanwhile the MDA levels in control and Cd-exposed gills at salinity 15 and 27 were not significantly different. The high level of MDA paralleled with the low activity of CAT at low salinity suggested that salinity played a protective role for shrimp under Cd exposure.