FREE MICROCYSTIN-LR AND ITS BIOACCUMULATION IN SOME FISH TISSUES, COLLECTED FROM SAGAR LAKE.

Abstract

Microcystis aeruginosa sp. (a Cyanobacterium) synthesizes the cyclic heptapeptide Microcystin- LR, a potent toxin toward humans and other animals. MC-LR is one of the most potent type of
isoform in nature with their potent hepatotoxicity and all the Microcystins are the potent
inhibitors of serine/ threonine protein phosphatase 1 and 2A. Fish are naturally exposed to MC
through ingestion of contaminated food and through dissolved toxins. In the present study MC- LR bioaccumulation, its distribution in the some tissues of Sagar Lake fishes has been reported. The MC-LR bioaccumulation was examined in the following fish Puntius ticto, Puntius
conchonious, Glossogobius giuris and Oreochromis mossambicus collected from the Sagar Lake.
Free form extractable MC-LR in fish tissue samples were examined by High Performance Liquid
Chromatography with a Photodiode Array Detector (HPLC-PDA). The mean concentrations of
MC-LR bioaccumulation observed in the muscles and the liver, significantly difference among
all fish species in which muscles shows the highest accumulation of the toxins. That fish species
are commercially important from the lake and they accumulate toxic MCs in tissues relevant to
human consumption. The average daily intake (ADI) of MCs in the muscles of all fishes
exceeded the human tolerable daily intake (TDI) 0.4µg/kg body weight per day set by World
Health Organization (WHO).