Evaluation of lead and cadmium bioaccumulations related to oxidative responses in the tissues of two wild mud crabs, Scylla olivacea and Scylla paramamosain, from Pattani Bay, Thailand

Exposure to heavy metals and bioaccumulation in the tissues can directly impact animal health and well-being.Mud crabs exhibit varying capacities for accumulating heavy metals and oxidative stress in their tissues due to their unique physiology and oxidative defense mechanisms.The present study investigated tissue oxidation in response to lead (Pb) and cadmium (Cd) accumulation in two types of wild mud crabs, Scylla olivacea and Scylla paramamosain.Samples were collected from the ecologically vulnerable, anthropogenically impacted region of Pattani Bay, Thailand.Muscles, gills, hepatopancreases, and gonads were dissected to evaluate metal content and oxidative status, including lipid peroxidation, reduced glutathione, superoxide dismutase, and catalase activities.Metal content in soil and water collected from the sampling area was analyzed.Results revealed that the hepatopancreas had the highest capacity for accumulating Cd and Pb in the two mud crab species.Hepatopancreases also exhibited the greatest sensitivity to oxidative stress, as evidenced by significantly elevated lipid peroxidation levels.S. paramamosain was more vulnerable to bioaccumulation than S. olivacea.Positive correlation has been indicated between soil Pb contamination and bioaccumulation in the muscles and gills of the two mud crabs.We concluded that Pb and Cd accumulate in a tissue-specific manner; the hepatopancreas was the most accumulative.Species-specific oxidative responses to heavy metal accumulation may be considered.S. paramamosain exhibited more sensitivity than S. olivacea.Moreover, S. paramamosain's oxidative response indicated some weakness characterized by a negative relationship between lipid peroxidation and reduced glutathione.