The Research Of Detoxication Of Dietary Vitamin C For Cadimium-Treatedsea Cucumber (Apostichopus Japonicus)

Trial 1 was conducted to determine the effects of cadmium(Cd) supplementationongrowth performance, antioxidant capacities and bioaccumulation of sea cucumber Apostichopus japonicus. Diets with five Cd levels(0, 10, 50, 100, and 500 mg Cd/kg dry weight) were fed to sea cucumber juveniles(4.10±0.02g) once a day for 30 days. The body weight gain(BWG) and specific growth rate(SGR) significantly(P< 0.05) decreased on the 500 mg Cd/kgtreatment group, but there were no significant differences(P >0.05)among other treatments.Moreover, high survival(> 95%) was observed in all groups.catalase(CAT) activity,glutathione peroxidase(GSH-Px) activity and Superoxide dismutase(SOD) activity in the coelomic fluid of sea cucumbers decreased with increasing dietary Cd concentration, but malondialdehyde(MDA) content inthe coelomic fluid increased. SOD activity,GSH-Px activity, and MDA contentshowedsignificantly(P< 0.05) differences between 10 mg Cd/kg and50 mg Cd/kg treatment groups. Cd accumulation increased in tissues of sea cucumbers with exposure time and concentrationand there weresignificantly(P< 0.05) differences between 10 mg Cd/kg and 50 mg Cd/kg treatment groups. The order of Cd accumulation in tissues was digestive tracts> respiratory tree > body wall.In conclusion,antioxidant capacity and bioaccumulation in sea cucumber were found to decrease and been induced in response to Cd. Sea cucumbers exhibited signs of Cd toxicity butno died occurred in response to 50 mg Cd/kg for 30 days.Trial 2 was conducted to determine thepotential protective effects of vitamin C(L-ascorbic acid, As A) against the effects of Cd on sea cucumbers. Diets with five As A levels(50 mg Cd/kg + 0 mg As A/kg, 50 mg Cd/kg + 3,000 mg As A/kg, 50 mg Cd/kg + 5,000 mg As A/kg, 50 mg Cd/kg + 10,000 mg As A/kg, and 50 mg Cd/kg + 15,000 mg As A/kg) were fed to sea cucumber(5.20±0.02 g) once a day for 30 days.The BWG and SGR of sea cucumbers fed the As A supplemented diet mixed with Cd were higher than the control group, but there are no significant differences(P >0.05)among As A treatments.Moreover, no mortality is observed in any groups.CATactivity, GSH-Px activityand SODactivityin the coelomic fluid of sea cucumbers increased with increasing dietary As A concentration,but MDA content inthe coelomic fluid decreased. Moreover, Cd accumulation in tissues decreased in response to dietary As A supplementation of treatments.In conclusion,vitamin C could mitigate the effects of Cd on sea cucumber. According to the bioaccumulation of sea cucumber tissues, it could be indicated that the optimum dietary vitamin C levelswas3,000-5,000 mg As A/kg when Cd levels was 50 mg/kg.