Tissue distribution and kinetics of dietary and waterborne zinc in abalone (Haliotis diversicolor supertexta)

Abstract

Uptake and depuration of dietary and waterborne zinc (Zn(II)) were examined in aquaculture abalone Haliotis diversicolor supertexta and red alga Gracilaria tenuistipitata var. liui using a simple first-order one-compartment bioaccumulation model. A six-compartment physiologically based pharmacokinetic model of the disposition of Zn(II) in abalone key organs was developed to predict tissue distributions. A mean residence time concept was also used to measure the biological persistence for disposition of Zn(II) in each target tissue. The one-compartment kinetic model was successfully fitted to determine uptake and depuration rates based on a 14-d exposure experiment. Results indicated that estimating uptake and depuration rates from depuration and short-term uptake experiments was a reliable method of predicting steady-state bioconcentration and biomagnification factors. Simulations using the six-compartment pharmacokinetic model for both water and food exposure routes indicated that the whole body Zn(II) concentration would reach equilibrium in about 120 d. Zn(II) however did not attain a steady-state in the soft tissue and the shell. It is concluded that a pharmacokinetic model is necessary for assessment of Zn(II) risk to abalone key tissues based on the Zn(II)-dynamics in target compartments.Uptake and depuration of dietary and waterborne zinc (Zn(II)) were examined in aquaculture abalone Haliotis diversicolor supertexta and red alga Gracilaria tenuistipitata var. liui using a simple first-order one- compartment bioaccumulation model. A six-compartment physiologically based pharmacokinetic model of the disposition of Zn(II) in abalone key organs was developed to predict tissue distributions. A mean residence time concept was also used to measure the biological persistence for disposition of Zn(II) in each target tissue. The one-compartment kinetic model was successfully fitted to determine uptake and depuration rates based on a 14-d exposure experiment. Results indicated that estimating uptake and depuration rates from depuration and short-term uptake experiments was a reliable method of predicting steady- state bioconcentration and biomagnification factors. Simulations using the six-compartment pharmacokinetic model for both water and food exposure routes indicated that the whole body Zn(II) concentration would reach equilibrium in about 120 d. Zn(II) however did not attain a steady-state in the soft tissue and the shell. It is concluded that a pharmacokinetic model is necessary for assessment of Zn(II) risk to abalone key tissues based on the Zn(II)-dynamics in target compartments.