Transfer of the coccidiostats monensin and lasalocid from feed at cross-contamination levels to whole egg, egg white and egg yolk

Abstract

Recent legislation has addressed the unavoidable carry-over of coccidiostats and histomonostats in feed, which may lead to the presence of residues of these compounds in eggs. In this study, laying hens received cross-contaminated feed at a ratio of 2.5%, 5% and 10% of the therapeutic dose of monensin and lasalocid for broilers. The eggs were collected during the treatment and depletion period and were analysed using liquid chromatography-tandem mass spectrometry. The different egg matrices were separated and analysed during the plateau phase. High lasalocid concentrations, which exceeded the maximum residue level, and low monensin concentrations were found in whole egg. Plateau levels were reached at days 7-9 for lasalocid and at days 3-5 for monensin. For lasalocid, the highest concentrations were measured in egg yolk; residue concentrations in egg white were very low.

Occurrence and Residue Concentration of Coccidiostats in Feed and Food of Animal Origin; Human Exposure Assessment

“…During 2005, an EU survey (Table 4) indeed reported LAS to be the most frequent coccidiostat found in eggs in the UK, being detected in 22.6% of egg samples [43]. A factor that may contribute to the accumulation of LAS in eggs is the great affinity for egg yolk shown by the molecule [25,44]. As well as not being previously reported for meat, simultaneous positivity for more than one anticoccidial has not been recorded for egg samples either.…”

Distribution of semduramicin in hen eggs and tissues after administration of cross-contaminated feed

“…This observation is a consequence of the mechanism and timeline of the egg production -the yolks are formed during the longer period, therefore it takes more time to reach the stable concentration of xenobiotics there (Kan & Petz 2000). Except monensin (Vandenberge et al 2012), all other ionophore coccidiostats tend to accumulate mostly in yolks. The yolk-to-albumen ratio varies from 3.2 for narasin (Kan & Petz 2000), to 18.5-30 for salinomycin (Akhtar et al 1996) to 197 for lasalocid (Vandenberge et al 2012).…”

“…Except monensin (Vandenberge et al 2012), all other ionophore coccidiostats tend to accumulate mostly in yolks. The yolk-to-albumen ratio varies from 3.2 for narasin (Kan & Petz 2000), to 18.5-30 for salinomycin (Akhtar et al 1996) to 197 for lasalocid (Vandenberge et al 2012). In some studies it was impossible to detect this ratio because the level in albumen was below the LOD.…”

Chemical amd physical hazards in the egg production chain in the Netherlands

“…The available residue studies on ionophores all show a strong correlation between the concentration in the feed and the plateau concentrations observed in the eggs, but there is a marked difference in their ability to accumulate (Kennedy, 1996;Vandenberge, 2012b;Rokka et al, 2005;Akhtar et al, 1996). Kennedy et al (1998) determined the relative ability of monensin, salinomycin and lasalocid to accumulate in eggs and found results of, respectively, 0.12, 3.3 and 63 μg/kg egg per mg/kg feed, indicating that lasalocid is much more readily transferable into eggs than salinomycin and monensin.…”