Studies on Disappearance of Malachite Green in Cultured Rainbow Trout

Abstract

Disappearance of malachite green (MG) from rainbow trout (Oncorhynchus mykiss) which had been bathed in 1ppm aqueous solution of MG for one hour was studied by high performance liquid chromatography. MG was rapidly absorbed from the gills and became widely distributed. The affinity of MG was high for liver and kidney and low for serum and muscle. The peak levels of MG in serum, liver and kidney were observed just after the bathing and the peak level in muscle was observed at 4 hours after bathing. MG in serum, liver and muscle gradually decreased with a lapse of time and fell below the detection limit (0.02μg/g) within 21 days after bathing. But in kidney, the excretion of MG was very slow and its level was still high (0.22±0.08μg/g) at 42 days after bathing. The excretion of MG from tissues of rainbow trout was much slower than had been found in previous studies.