Bioconcentration and depuration of cadmium in the selected tissues of rare minnow (Gobiocypris rarus) and the effect of dietary mulberry leaf supplementation on depuration

A 56-day trial was conducted to elucidate the bioconcentration and depuration of Cd in the liver and muscle of rare minnow (Gobiocypris rarus) and determine the effect of dietary mulberry leaf supplementation on depuration. Juvenile rare minnow were exposed to environmentally relevant doses of Cd (1 and 10 mu g/L) for 28 days of uptake and then allowed 28 days of depuration. The bioaccumulation factors of the treated rare minnow in the liver and muscle were calculated to be between 4.13-4.675 and 1.76-1.94, respectively. This results suggested that Cd had high potential for bioconcentration in rare minnow. To investigate the effect of dietary mulberry leaf supplementation on depuration, the remaining fish of each group were allowed to depurate with different ratios (0%, 10%, and 30% dry weight) of dietary mulberry leaf supplementation for an additional 28 days. Fish weights did not differ significantly (p > 0.05) between the control and mulberry leaf treated groups. Mulberry leaf powder did not significantly affect Cd depuration in the 10 mu g/L group or in the muscle of the 1 mu g/L group, but caused a significant decrease in Cd content in the liver of the 1 mu g/L group (p < 0.05). This work was the first to model the bioconcentration of Cd in rare minnow and showed that mulberry leaf supplementation decreased Cd residues in the liver of the 1 mu g/L group. Such a finding may promote the development of new approaches to mitigate the potential hazards of heavy metals to human health.