| In this article,for the problem of Semicarbazide(SEM)residues generally exceed the standard in crustacean aquatic products,we take Macrobrachium nipponense(M.Nipponese)with high concentration of SEM and large scale of culture in recent years as the research object.Carrying out a quantitative analysis of SEM in different tissues of M.Nipponese by optimizing high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS)to determine the background concentration level,distribution characteristics and existence characteristics of SEM in wild M.Nipponese from natural lakes,cultured M.Nipponese different growth stages and wild M.Nipponese of different genders.The research results provided basic data for the revision of the SEM residue limit standards in crustacean aquatic products and the establishment of sampling technical specifications.The main results are as follows:(1)Study on the characteristics of SEM in wild M.Nipponese from natural lakes: The concentrations of SEM in muscle,shell,hepatopancreas,gill,and eyestalks of M.Nipponese collected from natural lakes were investigated to study on the characteristics of SEM in wild M.Nipponese from natural lakes.The results show that: 1)SEM was widely detected in all tissues of wild M.Nipponese.The concentrations of SEM in muscle,shell,hepatopancreas,gill,and eyestalks are 1.62-4.18,93.42-288.01,3.32-23.29,4.05-13.56 ?g/kg and 33.72-65.17 ?g/kg.There are differences in the concentrations of SEM in M.Nipponese collected from different lakes.2)The distribution characteristics of SEM in tissues of wild M.Nipponese are: shell > eyestalks > gill / hepatopancreas > muscle.The concentration of SEM is highest in shell,and lowest in muscle.3)The proportions of free SEM to total SEM in muscle,hepatopancreas,gill,eyestalks and shell of wild M.Nipponese are: 46.96% ? 91.59%,35.73% ? 86.42%,34.22% ? 77.64%,3.56% ? 8.97% and 1.71% ? 6.66%.It's mainly free SEM in muscle and hepatopancreas,and mainly tissue-bound SEM in eyestalks and shell.(2)Study on the characteristics of SEM in cultured M.Nipponese from different growth stages: To explore the characteristics and variation of SEM in cultured M.Nipponese from different growth stages,the concentrations of SEM in muscle,shell,eyestalks,gill,hepatopancreas and cephalothorax of M.Nipponese of different growth stages collected from an aquaculture pond were analyzed.The results indicate that: 1)SEM was widely detected in all tissues of cultured M.Nipponese from different growth stages.The concentrations of SEM in muscle,shell,cephalothorax,eyestalks,gill and hepatopancreas are 6.88-17.11,107.30-306.09,100.29-116.15,85.27-122.82,48.43-85.60 ?g/kg and 13.51-25.94 ?g/kg.2)There are differences in the concentrations of SEM in M.Nipponese collected from different growth stages.With the development of cultured process,the concentration of SEM showed a trend of overall decline and local increase in muscle,and showed a trend of overall increase and local decrease in shell.3)The distribution characteristics of SEM in tissues of larvae are: shell > cephalothorax > muscle,and in tissues of adult are: shell > eyestalks > gill >hepatopancreas > muscle.The concentration of SEM is highest in shell,and lowest in muscle.4)For existence form,the proportions of free SEM to total SEM in muscle,hepatopancreas,gill,cephalothorax,eyestalks and shell of cultured M.Nipponese were 45.84% ? 83.51%,56.99% ? 92.47%,21.71% ? 31.99%,11.60% ? 24.54%,9.66% ? 14.64%,7.21% ? 14.99%.It's mainly free SEM in muscle and hepatopancreas,and mainly tissue-bound SEM in gill,eyestalks and shell.(3)Study on the characteristics of SEM in different genders M.Nipponese: To explore the characteristics of SEM in M.Nipponese of different genders,the concentrations of SEM in whole,muscle,shell,hepatopancreas,gill and eyestalks of male and female M.Nipponese were analyzed.The results were found as following: 1)The concentrations of SEM in whole,shell and eyestalks are significantly higher in females than in males,the concentrations of SEM in hepatopancreas are significantly lower in females than in males,but there are no significant differences in gill and muscle between male and female M.Nipponese.2)The distribution characteristics of SEM in tissues of male and female M.Nipponese both are: shell > eyestalks > gill / hepatopancreas > muscle.The concentration of SEM is highest in shell,and lowest in muscle.3)The existence characteristics of SEM in tissues in male and female M.Nipponese are basically the same,except in hepatopancreas and gill.It's mainly free SEM in muscle,and mainly tissue-bound SEM in whole,eyestalks and shell.In summary,the results show that SEM generally exists in all tissues of M.Nipponese from different sources.The concentrations of SEM in muscle and shell are 1.62-17.11,93.42-306.09 ?g/kg,which both exceed China's limit for SEM residues in animal-derived foods(1.0 ?g/kg).The distribution characteristics of SEM in tissues of M.Nipponese generally are: shell > eyestalks > gill / hepatopancreas > muscle.The concentration of SEM was highest in shell,and lowest in muscle.SEM is mainly tissuebound form in shell,and mainly free form in muscle.The concentrations of SEM in whole,shell and eyestalks are significantly higher in females than in males,but the concentrations of SEM in hepatopancreas are significantly lower in females than in males,there are no significant differences in gill and muscle between wild M.Nipponese of different genders. |
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