蛋白水解肽-金属配合物对虾类体内镉的脱除机制研究

Large quantity of heavy metals in shrimps are frequently happened above the demand of national standard, a kind of common phenomenon, which is one of the most dangerous threats to the shrimp breeding industry and the human health. In the study, the hydrolysis peptide-metal element complexes was prepared from Trichiurus haumela by-products and iron, zinc, calcium or magnesium element, based on the optimizing modification experiments. The removal mechanism of heavy metal elements from Procambarusclarkii shrimp was also studied, with hydrolysis peptide-metal element as the demetallization agent and cadmium (Cd) as the representing heavy metal. During the experiment, effect of hydrolysis peptide complexes on the removal rate of Cd, changes of physiological state and content of other essential metal elements in shrimps were further determined and evaluated. The achievements would provide theoretical references in order to evaluate the removal function of peptide complexes with metal element in the feed additives, fish and shellfish purification, or other animals temporary rearing, which were according with the key development direction of the exploitation of cheap aquatic resources, safety and quality control of aquatic products. For the present, there are not relevant references and patents about the removal of heavy metal elements from the shrimps by the hydrolysis peptide complexes with metal element. The purpose of the study is to make the breakthrough progress in this field.

虾类体内重金属超标现象严重，其已成为威胁我国虾类养殖业经济和人类身体健康的安全隐患之一。本项目以养殖克氏原螯虾为主要研究对象，带鱼加工副产物蛋白水解肽为原料，Fe、Zn、Ca及Mg为金属元素配体，优化金属修饰技术制备水解肽-金属配合物，进而通过水解肽-金属配合物对克氏原螯虾体内重金属镉（Cd）含量及结合状态、脱除代谢、虾生理状态及其他金属元素的影响研究，明确具有Cd脱除效果的水解肽-金属配合物类型及结构、制备技术及脱除作用机制，为新型养殖饲料添加剂及虾、贝及鱼类重金属脱除净化研究提供基础性资料。本项目研究符合低值水产资源高度开发与利用的重点发展方向，也符合水产品质量安全控制的发展方向。目前，国内外尚未发现关于蛋白水解肽-金属配合物脱除虾类体内重金属的研究及相关专利申请，课题组有望在此领域取得突破。

虾类体内重金属超标现象严重，其已成为威胁我国虾类养殖业经济和人类身体健康安全隐患之一。以螯虾和紫贻贝为对象，重点研究了水解肽-金属配合物对螯虾和紫贻贝Cd含量、脱除及虾生理状态等影响。取得结果如下：. 1、蛋白肽-金属配合物：酶解时间6h、pH6.5、温度45℃和加酶量20000u/g，水解度达71.3%。螯合温度30℃、pH7.0和30min时，配合物螯合率最高。纳滤分级：获得200~500、500~800、800~1100及1100~1500Da水解肽-金属配合物。. 2、鳌虾Cd 脱除：螯虾Cd富集表现为内脏团>肠>鳃>腹部肌肉>螯足肌肉。添加800和1200mg/kg TPH-Fe2+饲喂12d后，螯虾Cd脱除为肠>内脏团>鳃>腹部肌肉，脱除率为40.6%、36.1%、33.4%和10.2%。. 3、鳌虾生理状态：生长：1000mg/kg TPH-Fe2+饲喂60d后，螯虾成活率、增重率、特定增长率及出肉率分别提高10.1%、8.7%、0.29%/d及3.1%。免疫：饲喂60d，600mg/kgTPH-Fe2+对螯虾血清和肝胰腺中SOD、LSZ活力，表现出显著提高作用；添加1000mg/kg时，显著提高螯虾体内SOD、PO、LSZ和ACP酶活力。. 4、紫贻贝Cd脱出：富集第15d，紫贻贝内脏团、前闭壳肌、后闭壳肌、外套膜和鳃中，Cd含量为145、11、28、22和66 mg/kg。添加20mg/L TPH-Fe2+净化10d后，贻贝Cd脱除表现为鳃>内脏团>外套膜>前后闭壳肌，脱除率达41.0%、37.4%、29.9%和29.0%。. 5、Cd脱除机制：MT活性：TPH-Fe2+被机体吸收进入循环，争夺MT-Cd配合物中Cd，起到协助恢复MT活性、加速Cd排出。免疫增强：借助小分子肽类转运吸收机制，携带着Fe2+到达靶向器官，通过TPH和Fe2+增强机体保护性酶活性。生物利用度：TPH-Fe2+整体形式吸收，提高TPH、Fe2+在体内生物利用度，即在特定位点通过水解肽竞争螯合Cd、金属离子拮抗作用，加速Cd排出。. 研究成果为开发具有脱除重金属作用的饲料添加剂及鱼、贝类净化或暂养脱重金属专用剂等提供理论参考。