Toxicity Of Different Contents Of Lead In Feedsuff On Cyprinus Carpio Var.Jian And Effects Of Three Kinds Of Non-Metallic Minerals On Reducing Lead Toxicity

Lead pollution has become a major obstacle to restrict the development of aquaculture health. In this study, the toxic effeets of different contents of lead in feedstuff on Jian carp(Cyprinus carpio var.Jian) were investigated and in order to clarify the feed lead toxic effects on aquatic animals, to prevent the feed lead poisoning provide a scientific basis.In addition, the experiment was carried out to investigate the effectiveness of montmorillonite、zeolite and attapulgite clay.1Effects of different contents of lead in feedstuff on growth performance and enzyme activities of Jian carpThis research was conducted to investigate the effects of different contents of lead in feedstuff on growth performance, metabolic enzyme activities in serum (ALT, AST and LDH), MDA content and antioxidant defense systems of hepatopancreas of Jian carp. Four hundred and eight-three Jian carp (average initial weight,22.95±0.15g) were randomly divided into seven treatments and exposed to0,2,5,10,20,50and100mg/kg concentrations of Pb in diet for60days. The results show that weight growth ratio and feed conversation ratio were not significantly affected by Pb (P>0.05), but weight growth ratio presented a downward trend with the increasing Pb concentrations and feed conversation ratio presented a upward trend with the increasing Pb concentrations. After long term lead exposure, AST activity presented a upward trend with the increasing Pb concentrations, significant increase of AST activity were only found in100mg Pb/kg group (P<0.05), ALT and LDH activities presented a upward trend with the increasing Pb concentrations, significant increase of ALT and LDH activities were found in20,50and100mg Pb/kg groups (P<0.05). The results show that GSH-PX activity was induced by Pb, significant increase of GSH-PX activity activity were only found in100mg Pb/kg group (P<0.05). MDA content in hepatopancreas increased with the increasing Pb concentrations. SOD activity was induced by Pb. The results revealed that different contents of lead in feedstuff could lead Pb concentration-dependent toxicity on Jian carp. The change of the activities of metabolic enzyme activities in serum, MDA content and antioxidant defense systems of hepatopancreas canindicate Pb contamination in diet.2Effects of different contents of lead in feedstuff on Pb residues and content of Cu、Fe、Zn in liver and kidney of Jian carpThe conceptual design of raising was the same as that of the first experiment. The results show that Pb residues in tissues of Jian carp increased with the increase of Pb concentrations and the prolongation of exposure period. Pb accumulated in sampled tissues was the order as follows:posterior kidney> intestine> liver> gill> muscle. Pb concentration-dependent decrease in trace elements (Cu、Fe、Zn) content were observed in liver and kidney of Jian carp.In different sampled tissues, trace elements(Cu、Fe、Zn) metabolisms were disturbed at various levers. The results above suggest that Pb residues in kidney and liver can indicate Pb contamination in diet,long-term dietary Pb exposure could affect the content of Cu、Fe、Zn in liver and kidney.3Effect of non-metallic minerals on reducing lead toxicity of Jian carpThis study was conducted to compare the different capacities of lead adsorption of three non-metallic minerals. A total of5diets were adopted. Diet1was the control diet. Diet2was the control diet supplemented with100mg/kg lead. The other three were diet2supplemented with0.5%montmorillonite,3%zeolite and3%attapulgite clay, respectively. This study was tested in vitro and vivo, respectively.(1) The vitro study aimed to investigate the effects of different time, pH and concentrations on lead adsorption. The results indicated an increased adsorption rate with increasing time and pH in all absorbents tested. The adsorption rates of montmorillonite and attapulgite clay reached to saturation after120min. However, adsorption rates increased first then decreased with the increasing lead concentrations.(2) The vivo study aimed to investigate the effects of different absorbents on growth performance and tissue lead status on Jian carp (average initial weight:22.95±0.15g). Little difference was observed in survival rate. Weight gain increased12.02%,1.95%and1.80%, while feed conversation ratio decreased7.73%,6.70%and4.12%in fish fed montmorillonite, zeolite and attapulgite clay, respectively. Montmorillonite lowed lead concentration in muscle, liver, kidney, gill and intestine. Zeolite elevated gill lead concentration, but lowed that in liver, kidney and intestine. Attapulgite clay elevated muscle lead concentration, but lowed that in liver, kidney and intestine. From the above results, it could be concluded that montmorillonite is the best in lead adsorption among all the non-metallic minerals tested.