A study of the effect of individual feed constituents on the recovery of avoparcin from compound animal feedingstuffs

Fagan, Niall P.; McEvoy, J. D. G.; Lynas, Lorraine; Fitzpatrick, Deirdre; McCaughey, W.J.

doi:10.1039/a902128k

Cited by 2 publications

(1 citation statement)

References 2 publications

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“…Studies on the recovery of avoparcin from animal feeds (Fagan et al 1995) have highlighted problems with solvent extraction due to binding of the analyte with components of the feed matrix. More recent work with this drug has indicated that the relative proportion of individual feed components in a compound ration may dictate the extent of such binding (Fagan et al 1999).…”

Section: Discussionmentioning

confidence: 98%

Evaluation of a single plate microbiological growth inhibition assay as a screening test for the presence of antimicrobial agents in compound animal feedingstuffs at therapeutic and contaminating concentrations

Higgins

McEvoy²,

Lynas³

et al. 1999

Food Additives and Contaminants

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The Inhibitory Substance Test (IST), a microbiological growth inhibition test, is used for screening animal feedingstuffs for the presence of (contaminating) antimicrobial compounds. The effectiveness of the IST was established for 33 compounds that may be incorporated in feedingstuffs. Minimum detectable concentrations (MDCs) for standard solutions were established and compared with those obtained following solvent extraction of an antimicrobial-free compound feedingstuff spiked with each compound at 0-20 mg/kg. Of the 33 standard solutions examined, the test organism was not sensitive to 11 and the MDC for one was greater than its maximum inclusion rate in complete feedingstuffs. Following routine extraction (25% acetone-phosphate buffer) of feedingstuffs spiked with each of the 22 compounds to which the organism was sensitive, 10 were not detected, 15 were detectable at both minimum and maximum feed-inclusion rates and four were only detectable at their maximum feed-inclusion rates. Extraction with methanol (25%) had a deleterious effect with 12 compounds not detected, nine detectable at both minimum and maximum feed-inclusion rates and five detectable at their maximum feed-inclusion rates. Increasing acetone and methanol concentrations to 40 and 55% respectively resulted in larger inhibitory zones for antibiotic-free feedingstuff (25.3 + 2.43 mm vs 21.1 + 1.02 mm) compared with both 25% acetone (11.3 + 0.22 mm) and 25% methanol (11.2 + 0.22 mm), requiring the establishment of greater threshold zone diameters and negating any advantage in increasing the solvent concentration under these test conditions. It is concluded that the IST may be particularly useful for detection of a number of the zootechnical feed-additives recently banned in the EU, which, if used illegally, may be present at sufficiently high inclusion rates to facilitate detection. Further alteration of extraction conditions may improve the scope of the assay.

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Section: Discussionmentioning

confidence: 98%

Evaluation of a single plate microbiological growth inhibition assay as a screening test for the presence of antimicrobial agents in compound animal feedingstuffs at therapeutic and contaminating concentrations

Higgins

McEvoy²,

Lynas³

et al. 1999

Food Additives and Contaminants

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Accelerated solvent extraction of animal feedingstuffs for microbial growth inhibition screening for the presence of antimicrobial feed additives

Higgins

McEvoy

2002

Food Additives and Contaminants

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Three plate systems (combinations of indicator organism and growth medium) were evaluated for the detection of analytical standards of the banned feed additives avoparcin, bacitracin zinc, spiramycin, tylosin and virginiamycin. When authorized in the EU, the previously recommended minimum inclusion rate (MIR) for each compound was 5 mg kg(-1). One of the plate systems (Micrococcus luteus ATCC 10240, nutrient agar) detected all five additives. This plate was used in a further study that evaluated the suitability of accelerated solvent extraction (ASE) as a first step in the development of a rapid single-plate screening assay. A drug-free (negative control) feedingstuff was fortified with the compounds (0-50 mg kg(-1)), extracted by ASE and the extracts applied to the plate at each of three pH ranges - unadjusted extract (pH 5.7-5.9), pH 6.5 and 8.0. At pH 6.5, sub-MIR concentrations of virginiamycin and tylosin were detectable. Avoparcin was detectable at 6.3 mg kg(-1). The detection of zinc bacitracin was#10; pH-independent (10 mg kg(-1)). At pH 8.0, spiramycin was detectable at 5.4 mg kg(-1). Mean +/- SD analytical recoveries from fortified feedingstuffs (n = 10) ranged from 57 +/- 1.5% for avoparcin to 96 +/- 4% for virginiamycin. The five additives were also detectable following ASE extraction from a range of different feedingstuffs fortified with each of the drugs. A further 24 compounds permitted for use in animal feeds were tested. Of these, nine were detectable at their recommended MIR. It is concluded that ASE is a versatile technique suitable for the automated extraction of a range of antimicrobials from animal feedingstuffs. Employing ASE with this single-plate detection system permits the rapid antimicrobial screening of animal feedingstuffs and allows the detection of the banned additives. Whilst the method is applicable as a screening test, more specific postscreening methods would be necessary for subsequent identification (and quantification) of antimicrobials in screening-positive samples.

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A study of the effect of individual feed constituents on the recovery of avoparcin from compound animal feedingstuffs

Cited by 2 publications

References 2 publications

Evaluation of a single plate microbiological growth inhibition assay as a screening test for the presence of antimicrobial agents in compound animal feedingstuffs at therapeutic and contaminating concentrations

Evaluation of a single plate microbiological growth inhibition assay as a screening test for the presence of antimicrobial agents in compound animal feedingstuffs at therapeutic and contaminating concentrations

Accelerated solvent extraction of animal feedingstuffs for microbial growth inhibition screening for the presence of antimicrobial feed additives

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