| Laver is a kind of very popular seafood,rich in protein and trace elements,for example,high concentration of arsenic sugar.Although arsenic sugar is generally considered non-toxic,however,it is unclear whether high concentrations of arsenic sugar in laver maintains its stability,or arsenic sugar is demethylated and converted into more toxic methylated arsenic or inorganic arsenic after being ingested.Therefore,the study on the stability and transformation characteristicof arsenic sugar from laver has important theoretical and practical value for the evaluation of its intake safety.In this study,Fujian laver was chosen as experimental materials,mice was chosen as experimental model,the effects of different laver-containing mice feed and feeding methods on the stability and transformation characteristic of arsenic sugar from laver was investigated.The stability and metabolic characteristic of arsenic sugar from laver was analyzed through the determination of arsenic speciation in mice excrement collected on different time after the laver was ingested;the accumulation characteristic of arsenic speciation from laver was analyzed through the determination of arsenic speciation in mice organs collected in different feeding methods after the feeding was finished.Based on these results,the mass of arsenic speciation ingested by mice,discharged by mice excrement and accumulated by mice organs was calculated and the intake safety of arsenic speciation from Fujian laver was evaluated according to the LD50 of arsenic speciation in mice.The results of this study will provide a theoretical basis for the evaluation of intake safety of arsenic speciation from laver in human body.The main results are as follows:1.In mice excrement,laver arsenosugars DMAsSugarMethoxy was not detected after different laver-containing mice feed was ingested by mice under different feeding methods.Laver arsenosugars DMAsSugarMethoxy was quickly transformed to laver arsenosugars As1 under any kind of feeding methods after whether low or high concentration of laver-containing mice feed was ingested by mice,the concentration of laver arsenosugars As1 was slowly decreased after its highest concentration when the laver-containing mice feed was continuously ingested by mice for 1～2 days,the concentration of laver arsenosugars Asl was also the highest among the all arsenic speciation from mice excrement,accounting for more than 80%of total arsenic speciation in mice excrement.Under the same feeding method,the higher laver-containing mice feed,the higher concentration of arsenic speciation such as laver arsenosugars As1,dimethylarsinate[DMA(Ⅴ)]and monomethylarsonate[MMA(Ⅴ)]in mice excrement,however,the concentration of each arsenic speciation was quickly decreased to that in the excrement of control group mice fed by no laver-containing mice feed after the laver-containing mice feed was paused.Under different feeding methods,the total arsenic concentration in mice excrement was quickly increased with the beginning of laver-containing mice feed and quickly decreased with the pausing of laver-containing mice feed.Laver arsenosugars Asl was the predominant arsenic speciation in the excrement of experimental group mice fed by lower concentration of laver-containing mice feed,however,unknown arsenic compounds As2,As3 and As4 were also detected in the excrement of experimental group mice fed by higher concentration of laver-containing mice feed,which may be from the partial transformation of arsenosugars As 1 due to its unstability.2.In mice organs such as brain,meat,liver,kidney,heart and spleen,no laver arsenosugars DMAsSugarMethoxy or laver arsenosugars As1 were detected after different laver-containing mice feed was ingested by mice under different feeding methods.Arsenate[As(Ⅴ)]and DMA(Ⅴ)were the main arsenic speciation accumulated in mice organs except trace arsenite[As(Ⅲ)]in mice meat,the concentration of As(Ⅴ)and DMA(Ⅴ)was 44～398 μg kg-1 and 0～135～g kg-1 in mice organs,much lower than the LD50 of As(Ⅴ)and DMA(Ⅴ)in mice.3.61%～75%of arsenic intake by mice was discharged by mice excrement after different laver-containing mice feed was ingested by mice under different feeding methods.However,the total arsenic mass accumulated in mice organs,such as brain,meat,liver,kidney,heart and spleen,was lower than 0.1%of that ingested by mice.In summary,laver arsenosugars DMAsSugarMethoxy was quickly transformed to laver arsenosugars Asl after it was ingested by mice.Laver arsenosugars As1 was also unstable and partially transformed to unknown arsenic compounds As2,As3 and As4 after mice was fed by higher concentration of laver-containing mice feed.61%～75%of total arsenic mass was discharged by mice excrement after its intake,however,the total arsenic mass accumulated in mice organs was lower than 0.1%of that ingested by mice,the left arsenic may be discharged by mice urine or sweat.Therefore,arsenic speciation from Fujian laver could not be accumulated in mice body,which means that it is safe for people to eat laver. |
