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Determination of concentration levels of anticoccidials in eggs due to the presence of low levels of those compounds in feed for laying hens caused by carryover at the feeding mill. E. Daeseleire, L. Mortier, Ph. Delahaut and G. Huyghebaert. Anticoccidials.
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Determination of concentration levels of anticoccidials in eggs due to the presence of low levels of those compounds in feed for laying hens caused by carryover at the feeding mill E. Daeseleire, L. Mortier, Ph. Delahaut and G. Huyghebaert
Anticoccidials compounds that are widely used as feed additives to prevent and treat avian coccidiosis avian coccidiosis: • contagious amoebic disease affecting livestock • carried by unicellular organisms belonging to the genus Eimeria • causes poor weight gain, reduced egg production, intestinal lesions resulting in diarrhoea and related health problems, can cause death • most important parasitic disease in poultry Brussels, 03/05/2005
Legislation • Regulation (EC) N° 1831/2003 on additives for use in animal nutrition • although pure medicines, regarded as additives : not subject to MRL-legislation (MRL = maximum residue limit) • phasing out by 31/12/2012; Commission shall submit a report on the use of these substances as feed additives and available alternatives before 1/1/2008 • No MRLs available “zero tolerance” principle : no residues allowed Brussels, 03/05/2005
Selected compounds • diclazuril • nicarbazin • dimetridazole • halofuginone • robenidine main metabolite an equimolar mixture of Brussels, 03/05/2005
MS (mass spectrometry) • instrument : Quattro Ultima Pt • (Waters Micromass) • MS/MS : principle of MRM : fragmentation of precursor ion into product ions LC-MS/MS-method • HPLC (high performance liquid chromatography) • instrument : 2695 Alliance LC system (Waters) • conditions : Brussels, 03/05/2005
Mass spectrometric conditions Brussels, 03/05/2005
Animal experiment : • location: Department of animal nutrition and husbandry, Merelbeke • Laying hens : ISA-brown, selected on egg production and body weight, in week 30 of laying cycle at start of the experiment • Period of adjustment : 4 weeks before the experiment hens were placed in the cages • feed : mash of 11.7 MJ MEn/kg, containing 16 % crude protein • housing : 4 hens/cage, conventional conditions of ventilation, temperature (18-22°C) and light (16h light/day) Brussels, 03/05/2005
dimetridazole : only 1 group (100%) as this is a forbidden compound (Annex 4) • GROUPS : 5 compounds diclazuril, halofuginone, robenidine, nicarbazin, dimetridazole x 2 concentrations/compound 100% (= max. conc. in feed), 5% (carry-over) + blank group TOTAL : 10 groups x 12 hens/group Brussels, 03/05/2005
PREPARATION OF FEED : at DVV • per group 40 kg feed was prepared • first 5 %, than 100 % concentration • between 5 % and 100 %, 3 rinses were scheduled • between 2 different compounds, 5 rinses were done • ANALYSIS FEED SAMPLES : • feed samples were analysed with a validated LC-MS/MS method • the rinses in between were negative : no carry-over took place Brussels, 03/05/2005
results analysis feed containing anticoccidials : Brussels, 03/05/2005
a. halofuginone Brussels, 03/05/2005
b. dimetridazole Brussels, 03/05/2005
c. robenidine Brussels, 03/05/2005
d. narasin Brussels, 03/05/2005
e. nicarbazin (dinitrocarbanilide) Brussels, 03/05/2005
f. diclazuril Brussels, 03/05/2005
Advice 24-2004 of the scientific committee of the Belgian Federal Food Agency: action limit of 10 µg/kg for diclazuril, narasin, nicarbazin and robenidine Brussels, 03/05/2005