Metallothionein as a bioindicator of heavy metal exposure in the tropical shrimp, Penaeus vannamei: A study of dose-dependent induction

Induction of metallothionein (MT) in the hepatopancreas of the tropical, commercially-farmed shrimp (Penaeus vannamei,) was studied in the laboratory after exposure to waterborne cadmium. MT was quantified with differential pulse polarography. Two laboratory experiments were performed: a dose-response and a time-course experiment. MT was significantly induced in a dose-dependent way in response to waterborne CdCl2. In the time-course experiment a significant correlation was found both between induced MT and accumulated cadmium in the hepatopancreas, and between depuration of MT and cadmium. Final value of MT after 9 days of exposure to 1.50 mg Cd/litre was 5600 μg MT/g wet weight hepatopancreas, which is an induction of 180%.