The Depuration Rules of the Metabolites of Furazolidone and Nitrofurazone in Turbot Scophthalmus maximus

The depuration rules of the metabolites of nitrofurazone and furazolidone,semicarbazide(SEM)and 3 -amino-2-oxazolidinone(AOZ),in muscle,liver and blood of turbot Scophthalmus maximus were studied,by different exposure types.The results showed that both nitrofurazone and furazolidone could accumulate in the tissues of turbot,then metabolite rapidly to SEM and AOZ,respectively.And the average concentrations of these two metabolites in liver were much higher than that in muscle and blood,while the concentrations of AOZ were much higher than that of SEM in the same tissue,and the former was about 10-30 times higher than that of the latter.Moreover, the depuration of SEM and AOZ represented similar rules no matter what exposure type:the residues depurated rapidly at first,then the depuration rate reduced and the concentrations maintained for a long time,which still were higher than detection limit when the experiment ended.However,the concentrations and depuration rates of SEM and AOZ could be determined by the exposure types,which might be explained by that the concentrations of SEM and AOZ when turbot only exposed to nitrofurazone or furazolidone were much higher than that of SEM and AOZ when turbot exposed to these two chemicals synchronously,while the depuration half-life of SEM and AOZ were just on the opposite.Therefore,it is difficult for the nitrofurans' metabolites to depurate in tissues of turbot, which present the fact that more attentions will be paid on the using of these chemicals on turbot.