Effect of Chinese parsley Coriandrum sativum on cadmium binding to proteins from the liver and kidney of rainbow trout Oncorhynchus mykiss

Previous reports have shown that solid-form feed mixture with added Chinese parsley (CP) had no influence on either the growth or health of rainbow trout, and the cadmium (Cd) taken up by the fish was, remarkably, reduced by 12-48% in comparison with the control group. In this study, soluble fractions from the liver and kidney underwent gel filtration, and changes of Cd, Cu, and Zn concentrations over time for each fraction, and the relationship between the form of Cd that accumulated in tissues and its toxicity, were measured. A nontoxic metallothionein fraction (MTF) of 7 kDa and a high molecular weight fraction (HMF) of about 60 kDa were isolated from the soluble fractions. The induction of nontoxic MT-Cd was 1.6 times higher (p<50.05) in the CP added group than in the control group. Moreover, Cd present in the HMF from the CP addition group also increased from the 3rd week and was 1.7 times higher by the 12th week (p<0.05), even though the HMF was reported to hardly or slightly bind to Cd. These findings suggest that the interaction with several ingredients in CP may contribute to bind metallothionein (MT) and reduce the toxicity of harmful heavy metals, without effect on fish physiology.