Determination of regulatory ionophore coccidiostat residues in feedstuffs at carry-over levels by liquid chromatography-mass spectrometry

Abstract

In this study samples of feedstuffs were collected from different feed mills and animal farms located in central Italy and analyzed for ionophore coccidiostat residues at carry-over levels by liquid chromatography-mass spectrometry. Since unavoidable cross-contamination of feedstuffs may occur during their production as well as distribution and storage, the collection of samples covered all these different stages. Residues of lasalocid, monensin, salinomycin and maduramicin were detected in 32.4% of samples, both at production and storage level. The maximum content for unavoidable carry-over set by Regulation (EU) No 574/2011 was exceeded in 11.3% of samples. The variability of the results highlighted the different approach of each investigated feed business operator to avoid any cross-contamination in non-target feed. The method developed in this study can be able to detect ionophore coccidiostats at low concentrations consequent to carry-over.

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

“…Among ionophoric molecules, the most frequently detected coccidiostat in untreated feed was LAS, found in 11 samples, one of which exceeded the regulatory limit, followed by NAR found in 7 samples of which one was a noncompliant sample (Table 3). These results diverge from those reported by Annunziata et al [1] and Moretti et al [23] who found MON as the most frequently detected carry-over ionophore coccidiostat in feedstuff collected according to Italian NRCP (22% and 35%, respectively).…”

“…It is to be noticed that the non-compliance rate varies mainly as a result of an increase in samples tested during the years examined, rather than an effective decrease in positive samples. Ionophoric molecules were detected in 28 feed samples (10.4%), while non-ionophoric molecules were found in 54 samples (20.15%); these results differ from those reported by Annunziata et al [1] for ionophoric compounds (32.4%) and are comparable to those reported by the same authors in 2018 [36] for non-ionophoric residues in feed samples (20.3%) collected as part of the official Italian monitoring plan in other regions of Italy. Among ionophoric molecules, the most frequently detected coccidiostat in untreated feed was LAS, found in 11 samples, one of which exceeded the regulatory limit, followed by NAR found in 7 samples of which one was a noncompliant sample (Table 3).…”

“…Coccidiostats are pharmacologically active molecules employed, since 1940, to prevent and inhibit parasitic protozoa of the genus Eimeria , referred to as coccidia, causing a very contagious disease of the gastrointestinal tract in many farmed animals [1,2]. Coccidiosis represents a major disease in poultry, causing intestinal lesions, scarce weight gain, poor feed conversion and poor egg production; in its acute form, coccidiosis causes high mortality rates [3,4,5,6,7].…”

“…Aside from intensively farmed animals, such as poultry, coccidiosis also affects extensively reared species including sheep, cattle, pigs and rabbits [2]. Coccidiostats are authorized as feed additives for target animal species by European legislation [8] and can be categorized as polyether ionophores produced by the Streptomycetaceae bacteria family, such as monensin (MON), narasin (NAR), lasalocid (LAS), salinomycin (SAL), semduramicin (SEM) and maduramicin (MAD), or as non-ionophoric synthetic molecules such as halofuginone (HFG), robenidine (ROB), diclazuril (DIC), decoquinate (DEC) and nicarbazin (NIC) [1,2]. Each coccidiostat has individual toxicological characteristics which are based on the molecular mechanisms of action that affect trans-membrane ion transport in the case of the ionophoric compounds.…”

Ionophore coccidiostats – disposition kinetics in laying hens and residues transfer to eggs

“…Several studies have reported that feed cross-contamination with a carryover of ionophore coccidiostats has been identified as the most common source of exposure in laying hens ( Kennedy et al, 1996 ; Borràs et al, 2011 ; Rokka et al, 2013 ; Spiegel et al, 2013 ; Roudaut and Fournet, 2017 ; Roila et al, 2019 ). It is widely accepted that under practical conditions in feed mills during the production of medicated and non-medicated feeds in the same line of production, some traces of the medicated feed batch may remain in the production line, and this carryover can contaminate subsequent batches of non-medicated feed ( Kennedy et al, 1996 ; Borràs et al, 2011 ; O'Mahony et al, 2012 ; Annunziata et al, 2017 ). The risk and degree of cross-contamination depend on the equipment and methods used in the feed mill as well as the electrostatic properties of the premix formulation ( HAFEZ, 1991 ; Kennedy et al, 1996 ).…”