Studies On The Toxicity Of Dehydroacetic Acid And Its Residue Elimination In Chicken Tissues

Dehydroacetic acid (DHA) has been widely used as food preservative because of its broad antimicrobial spectrum. Aim to be used as a fungicide in feed, the basical toxicity and the residue dynamics of DHA in chicken tissues were investigated. The results may provide safety data for DHA used as a feed additive and technical means for the monitoring of the DHA residue elimination in the future.The acute toxicity test, micronucleus test and Ames test were made to estimate DHA toxicity. The LD50 of dehydroacetic acid measured was 1313.26 mg/kg with 95% trust range 1129.63～1526.75 mg/kg. The dose of 1/2 LD50,1/5 LD50,1/10 LD50 DHA were administrated to mice in micronucleus test. Beside of 1/5 LD50,1/10 LD50 DHA groups, the 1/2 LD50 group was obviously different from normal mice (P< 0.05), but there were not dose-effect relationship within three doses of DHA groups. The micronucleus test and Ames test of DHA were observated a negative result.A high pressure liquid chromatography (HPLC) method was established to determine the residue of DHA in muscle, liver and kidney tissues of chicken. The tissue samples were extracted with acetonitrile, liquid-liquid extraction by hexane, purified by PAX solid phase extraction column. The residues were dissolved in acetonitrile for HPLC detection. A C18 column with ultraviolet absorption detection at 290 nm, using methanol-water which includes 0.02% ammonium acetate(20/80,v/v) as eluent was used in HPLC. A linear calibration curve with coefficient relation (R2≥0.9996) in the range of 0.2～50 mg/L of DHA concentration was made. When DHA was added to tissues at dose of 0.5, 1.0 and 5.0mg/kg, average recoveries in different tissues were ranged from 68.28% to 93.49%,with CV% ranged from 3.38% to 7.94% within-day and 4.31% to 7.80% between-day. The limit of detection (LOD) and limit of quantitation of DHA were observed at 0.1 mg/kg and 0.2 mg/kg respectively.In order to study the residue elimination of DHA in chicken tissues, DHA was fed to Huangyu broiler for 2 weeks at two doses of 0.3g/kg and 0.6g/kg, and then the concentrations of DHA in chicken tissues were detected by the method introduced above. The results indicated that there was no obvious difference in residue of DHA in same tissues between two doses, and the residue of DHA in tested tissues eliminated slowly. The liver was the main target tissue of DHA residues. DHA residues in muscle and kidney were at comparative low levels, and were eliminated faster than that in liver. The content of DHA in kidney was lower than LOD after 11 days withdrawal time, that in muscle was within 13 to 15 days, that in liver was after 17 days withdrawal time.