Oxidative response to cadmium and lead accumulations in the tissues of blue swimming crabs Portunus pelagicus from the Trang Province coastline, Southern Thailand.

Abstract

Metals have been reported to alter the oxidative status of both redox-active and redox-inactive metals accompanying oxidative stress induction. In aquatic ecosystems, metal contamination is regarded as serious pollutants and bioaccumulation, especially when aquatic seafood products are involved, which results in human risk. The blue swimming crab Portunus pelagicus is a highly popular crab species for consumption as seafood in Thailand. The meat parts and the hepatopancreas (HP) together with gonad are consumed and in high demand. Therefore, the present study aimed to investigate bioaccumulation of cadmium (Cd) and lead (Pb) along with tissue oxidative responses in P. pelagicus. Sixty-seven samples of P. pelagicus were obtained from small-scale fishers along the coastline of Trang Province. Bioaccumulation of Cd and Pb and oxidative response in gill, muscle, and HP + gonad were evaluated. Cadmium and Pb accumulation levels were highest in the HP and gonad, followed by the gill and then muscle, indicating that Cd and Pb have a high affinity to be concentrated in the HP and gonad. An organ-specific oxidative response to Cd and Pb accumulation was demonstrated in which Cd significantly activated superoxide dismutase (SOD) activity in the gills and muscle tissue, while Pb significantly activated the SOD activity only in the HP and gonad. Only Cd accumulation in gill tissue represented a significant activation of lipid peroxidation, as indicated by the malondialdehyde level. This study implied that P. pelagicus exhibits an "adaptive stage" in the oxidative response of tissue due to metal accumulation. Additionally, the data presented here further indicate that the consumption of only the meat parts and removal of the HP and gonad would reduce human exposure to metal toxicity.