METALLOTHIONEIN AS A BIOINDICATOR OF HEAVY-METAL EXPOSURE IN THE TROPICAL SHRIMP, PENAEAUS-VANNAMEI - A STUDY OF DOSE-DEPENDENT INDUCTION

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