MALACHITE GREEN - A PHARMACOKINETIC STUDY IN RAINBOW-TROUT, ONCORHYNCHUS-MYKISS (WALBAUM)

Pharmacokinetic studies on uptake, distribution and elimination of mal achite green in rainbow trout, Oncorhynchus mykiss (Walbaum), are desc ribed. All three processes were found to be temperature-dependent, wit h levels and rates increasing with increases in water temperature. Tis sues investigated were serum, liver, kidney, muscle and viscera. First -order kinetics were found to apply and, in particular, kidney was obs erved to be a deep compartment. The long-term persistence of kidney re sidues may explain the efficacy of malachite green for the control of proliferative kidney disease in rainbow trout. Residue levels in muscl e were never excessive and an extrapolation from the experimental data suggests that a suitable withholding period might be 600 degree days.