Study On The Characteristics Of Pb And Cd Enrichment And Release In Water And Feed Of Penaeus Vannamei

Vannamei is of one of the largest number among the crustaceans raised by humans. Meanwhile, as a high-quality aquatic product, vannamei food safety is getting more and more attention. Among the concerned issues, the heavy metal pollution influences the food safety greatly. Heavy metal pollution is easy to accumulate, but difficult to degrade, which has high toxicity for human health. In order to investigate the danger of the metal pollution to the vannamei, metals are put in the sea and feed, and the enrichment and the release of different concentrations of Pb and Cd are studied. We hope that this study can provide help for the scientific breeding of the vannamei and the improvement of its food safety.The contents and results of the study are as follows:This is a two-factor, four-level experiment, it was carried out on four concentrations of Pb and Cd in feed and-sea-water, wherein, Pb concentrations in the feed are 2.089 mg/kg,2.75 mg/kg,6.103 mg/kg,14.52 mg/kg, and concentrations in the seawater are 0.0015 mg/L,0.0080 mg/L,0.0466 mg/L,0.2302 mg/L; Cd concentrations in feed are 0.997 mg/kg,2.565 mg/kg,3.332 mg/kg,9.976 mg/kg, concentrations in the seawater are 0.00015 mg/L,0.00084 mg/L,0.00448 mg/L, 0.02282 mg/L. This experient was divided into 16 groups,30 d of accumulation and 27 d of release.Accumulation and release of Pb and Cd in liver, exoskeleton and muscle are studied by using two-compartment bioconcenetration model. Through the study,we can obtained kinetic parameters:heavy metal uptake rate constant (ki), extracting rate constant (k2), bioconcentration factor (BCF) and biological half-lives period(B1/2), equilibrium concentration of heavy metals in vivo CAmax by non-linear curve fitting.In enrichment stage, heavy metals concentrations in the feed and seawater have great influence on the interaction. The Pb and Cd concentration in the seawater play dominant roles in heavy metal accumulation, as to feed, its role seems less more important. In the release stage, interactions in different organs and release times are striking. Pb and Cd are accumulated selectively in the major organs and tissues in Vannamei and liver pancreas accumulate more than other organs. Obvious concentration of Pb and Cd is found in Vannamei and the concentration of heavy metals in liver, exoskeleton and muscle exhibits an apparent positive correlation to accumulation time as well as the exposure concentration of heavy metals. There is a notable difference after a certain period of accumulation time, and the general concentration quantity trend is that:liver> muscle.