| With the rapid development of modern industry and agriculture,arsenic pollution is becoming more and more serious,making arsenic enter the water environment through waste,which seriously affects the quality and safety of aquatic organisms and the healthy development of aquaculture.Chinese mitten crab(Eriocheir sinensis)is popular with consumers for its unique taste,but as an important benthic-life crustacean,the enrichment of heavy metals is often higher than other aquatic organisms.However,there is a lack of research on the arsenic exist speciations,bioaccumulation,transformation and toxicity mechanism in Eriocheir sinensis.The toxicity of arsenic is closely related to its form.Normally,inorganic arsenic toxicity is higher than organic arsenic,while trivalent arsenic toxicity in inorganic arsenic is higher than that of pentavalent arsenic.Therefore,the identification and analysis of arsenic form in Chinese mitten crab can scientifically and reasonably evaluate the dietary risk and safety in Chinese mitten crab.In our study,the distribution of six arsenic forms(As(Ⅲ),As(Ⅴ),MMA,DMA,ASC,ASB)in the main domestic breeding Chinese mitten crab was determined by HPLC-ICP-MS.The source of arsenic in Chinese mitten crab in Anhui Province was traced back.The residue and transformation characteristics of arsenic among different tissues were studied by exposure experiment of inorganic arsenic.Finally,the metabolomics was studied of hepatopancreas tissue to found the arsenic toxicity mechanism in Chinese mitten crab.The main results are as follows:(1)Chinese mitten crabs in freshwater culture basins in China were investigated to survey the total arsenic and arsenic residues.The results showed that the detection rate of total arsenic was 100%,the concentration range was between 0.50-1.38 mg/kg.The six arsenic forms accounts for the most,and As B is the main arsenic form.The highest inorganic arsenic value is 0.209 mg/kg,but not exceed the country standard to the limit of inorganic arsenic in crustacean.THQ value showed that was much less than 1,which indicated that intaking these crabs would not cause obvious health risk to human body.(2)In order to explore the source of arsenic in Eriocheir sinensis,crab,sediment,water,fresh fish,feed,corn(soybean)and water grass were collected in Anhui main breeding base.The total arsenic and arsenic speciations of all the substrates were measured.The results showed that the content of total arsenic in the collected medium was water > sediment > feed >fresh fish > crab > water grass > corn(soybean),and the average content range of total arsenic in water was 3.072-12.520 μg/L.The highest arsenic form is As(Ⅴ)and its content is 0.054-5.831 μg/L,followed by DMA,and other arsenic forms were detected in a small amount.The average content of total arsenic in sediment samples was 0.476-4.627 mg/kg.The detection rates of As(Ⅲ)and As(Ⅴ)were 100%,the concentration range was 0.033-0.526 mg/kg and0.008-0.526 mg/kg respectively.The detection rates of MMA and DMA were about 50%,while organic arsenic were detected in a small amount.The main arsenic form in feed and ice fresh fish were As B,but inorganic arsenic was a little content.All arsenic speciations detected a little amount in corn and soybean.(3)In order to further study the enrichment and transformation of arsenic in different tissues(leg muscle,chest muscle,liver pancreas and gonad)of Eriocheir sinensis,the As(Ⅴ)exposure experiment was conducted for five weeks in mature Eriocheir sinensis.After collection every time,the arsenic speciations content of different tissues were measured.Data analysis showed that As B was the main arsenic form in four tissues,and the concentration of As C was the lowest,the other four arsenic forms had significant differences among different tissues.The content of As(Ⅴ)in different tissues was muscle > hepatopancreas ≈ gonad,and As(Ⅲ)content was hepatopancreas > muscle > gonad.As(Ⅲ)and As(Ⅴ)content in leg muscle and body muscle were difference in different gender Chinese mitten crab.For MMA and DMA,hepatopancreas > gonad ≈ leg muscle ≈ body muscle.There was no significant difference of organic arsenic in all the edible parts of Eriocheir sinensis.(4)Finally,in order to reveal the mechanism of arsenic toxicity to Eriocheir sinensis,the non-target metabolomics and lipid metabolism were analyzed in the hepatopancreas of crab.The results of non-targeted metabolism group showed that the difference metabolites among the Eriocheir sinensis control group and high arsenic group were mainly fatty acids,phospholipids,amino acids,ceramide,oxidized glutathione and leukotriene D4.The different metabolic pathways include protein digestion and absorption,sphingomyelin signaling pathway,ammonia t RNA biosynthesis pathway,bile secretion.The metabolic results of the lipid group showed that the difference metabolites of crab between the control group and the high arsenic group were sphingomyelin ceramide and phospholipid triglyceride,phosphatidylcholine,phosphatidylinositol and phosphatidylethanolamine hemolytic phospholipids.The different metabolic pathways include glycerin phospholipid metabolism,sphingomyelin signaling pathway,fat decomposition regulation and cholinergic metabolism in cancer.The toxic effects of arsenic on Eriocheir sinensis are different in gender,which may be related to the individual size,metabolism and physiological structure of crab.In this paper,the background value of arsenic speciation in Chinese Mitten Crab was investigated,providing a numerical basis for the study of arsenic speciation in freshwater crustacean.Furtherly,we traced the source of arsenic speciation residues in Chinese mitten crab can make suggestions for reasonably improving the surrounding culture environment of crab.Finally,the enrichment and transformation of inorganic arsenic in Chinese mitten crab were studied so that can assess the dietary risk and provide reference for reasonable diet. |
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