Correlation On The Residue Depletion Of Roxarsone In Fur, Body Liquids And Edible Tissues Of Swine

Roxarsone is an anthropogenic organic-arsenic compound that is used widely as an additive to poultry and swine feed for anti-coccidiosis and for improved feed efficiency. The FDA regulated the MRL of roxarsone is 2mg/kg in kidney and liver tissues,is 0.5mg/kg in muscle and other tissues.If the tolerance is exceeded,the carcass may not be used for human food.A preslaughter test for total arsenic in an easily accessible biological fluid is needed to predict if the concentration of total arsenic is below tolerance in the edible tissues before the swine is slaughtered.The aim of current study is finding the rule of residue depletion in the edible tissues and surface tissues of swine.Find a suitable surface tissue which the rule of depletion the same as edible tissues by animal experiment.And construct the residue correlation between this surface tissue and edible tissues.In practice,a detection applied to a pre-slaughter surface tissue sample collected from a suspect animal should be able to predict if the edible tissue sample of the same animal slaughtered at this time would be below tolerance - and safe for human food or greater than tolerance-leading to a requirement for increased drug elimination time.In current study,two detection methods were developed.One was developed for directly detection of total arsenic in edible tissues and surface tissues of swine by microwave digestion couple with hydride generation-atom fluorescence spectrometry. Another method was developed for indirect detection of roxarsone in edible tissues and surface tissues of swine by hydride generation-atom fluorescence spectrometry couple with organic-solvent extraction system and microwave digestion system.The limit of detection of instrument was 0.0133μg/kg.Recoveries of total arsenic determination method ranged from 92%to 111%,Intra-day coefficients of variation(CV)(under repeatability conditions) ranged from 2.8%to 7.9%.Recoveries of parent drug determination method ranged from 80%to 102%,Intra-day coefficients of variation(CV) (under repeatability conditions) ranged from 4.2%to 10.3%.Roxarsone was administrated to swine in medicated feed at the level of 100mg/kg for successive 7 days,the upper two methods were used to determine the residue of parent drug and total arsenic in muscle,liver,kidney,urine,feces and hair.The concentrations of total arsenic in edible tissues were high,but the concentrations of parent drug in edible tissues were low.This result indicated the roxarsone exist as metabolites in animal body. The concentration of total arsenic of in edible tissues was:liver＞kidney＞muscle.The concentrations of roxarsone and total arsenic were high,this indicated the roxarsone could not be absorbed and drugs were almost excreted directly by feces.The depletion rates of total arsenic in kidney,liver and muscle were 0.14d^-1,0.11d^-1 and 0.05d^-1,respectively. This indicated the rate of depletion of total arsenic in edible tissues was:liver＞kidney＞muscle.The depletion rates of total arsenic in feces and urine were 0.13d^-1 and 0.11d^-1, respectively.This indicated the rate of depletion of total arsenic in surface tissues was: feces＞urine＞hair.Urine and feces were selected as optimal surface tissue according to the rate of depletion.In fast elimination phase,correlation equation for urine vs.kidney,urine vs. liver,feces vs.kidney and feces vs.liver were y=1.01x+326.7,y=1.90x+448.9,y= 0.26x+605.1 and y=6.43x-2624.7,respectively,correlation coefficients for urine vs. kidney,urine vs.liver,feces vs.kidney and feces vs.liver were 0.9916,0.9784,0.9763 and 0.9902,respectively;In slow elimination phase,correlation equation for urine vs. kidney,urine vs.liver,feces vs.kidney and feces vs.liver were y=2.75x+23.28 and y= 5.04x-6.33,yk=0.97x+83.1 and yL=1.83x-207.8,respectively,correlation coefficients for urine vs.kidney,urine vs.liver,feces vs.kidney and feces vs.liver were 0.9973,0.9960,0.9946 and 0.9724,respectively.The result of F-test of regression analysis was shown to be significant(P＜0.01).The result of F-test of estimated and measured concentrations was shown to be non-significant(P＞0.05).There was no correlation for urine or feces vs.muscle.These two methods are enough simple and sensitive.At the same time,it can provide the reference of determination of other organic-arsenic compound in other edible animal. The experiment of depletion studied the rule of depletion of arsenic in swine in detail. The correlation of urine vs.edible tissues and feces vs.edible tissues presented linear relationship,The result of F-test of regression analysis was shown to be significant (P＜0.01).The result of t-test of estimated and measured concentrations was shown to be non-significant(P＞0.05).Correlation date can guide the pre-slaughter detection in practice and has a high significance.