Oxidative effects and toxin bioaccumulation after dietary microcystin intoxication in the hepatopancreas of the crab Neohelice (Chasmagnathus) granulata

We studied the accumulation and depuration of microcystin-LR (MCLR) in the hepatopancreas of the crab Neohelice granulate fed twice weekly with either non toxic or MCLR-producing Microcystis aeruginosa (strain NPDC1 or NPJB, respectively) during seven weeks. We also analyzed MCLR effects on the oxidative stress- and detoxification-related variables, superoxide dismutase and glutathione-S-transferase activities, and the levels of reduced glutathione and lipid peroxidation (as thiobarbituric acid reactive substances, TBARS). Hepatopancreas MCLR content slightly increased during the first three weeks, up to 8.81 +/- 1.84 ng g(-1) wet tissue mass (WTM) and then started to decrease to a minimum of 1.57 +/- 0.74 ng g(-1) WTM at the seventh week (p < 0.05 with respect to that in the first week). TEARS levels were about 55% higher in treated than in control N. gnmulata (p < 0.001 and p < 0.05) during the first three weeks of the experimental period. GSH content became 50% lower than in control individuals (p < 0.01) during weeks 6 and 7. SOD activity was increased by about 2-fold (p < 0.05 or p < 0.001) from week 3 to 7 in treated crabs with respect to control ones, while GST activity was about 70% higher in treated than in control crabs from week 4 to week 7 (p < 0.05). Our data suggest that in the hepatopancreas of N. granulate Malt accumulation and oxidative damage are limited and reversed by detoxification-excretion and antioxidant mechanisms, The activation of these defensive mechanisms becomes evident at 3-4 weeks after the start of the intoxication. (C) 2015 Elsevier Inc All rights reserved.