An enzyme immunoassay technique for the determination of sulphadimidine in animal feedstuffs has been developed. The antibody showed limited cross-reactivity with other drugs, including sulphonamides, used as feed additives. Using spiked samples recoveries of 80-88% were obtained. The limit of detection of the assay was 70 ng/g.

Animal Feed↗

PubMedDate not supplied

Residues of the beta-agonist clenbuterol in tissues of medicated farm animals.

Reports of the illegal use of clenbuterol as a growth promotant prompted the development of a competitive enzyme immunoassay for this drug. This procedure was utilized to study the elimination of clenbuterol from tissues in sheep medicated with both therapeutic and growth-promoting doses of the drug. The results indicated that prior to removal of medication clenbuterol was widely distributed throughout the animal tissues. However as the withdrawal periods increased fluid targets such as urine and bile became less effective at detecting clenbuterol usage. At both therapeutic and growth-enhancing concentrations of clenbuterol liver samples remained positive up to the maximum withdrawal time given in this experiment (15 days). Concentrations of clenbuterol likely to cause food poisoning (> 100 ng/g) were only detected in liver samples taken prior to the removal of medication. The highest recorded concentration of clenbuterol in muscle was 22.5 ng/g.

Animals↗

PubMedDate not supplied

The production of pig tissue sulphadimidine reference material.

The production of stable homogeneous reference materials containing the antimicrobial agent sulphadimidine in pig tissue is described. These were commissioned by the Community Bureau of Reference (BCR), established by the Commission of the European Communities, to promote improvements in analytical accuracy and to ensure uniformity of results determined by member states. Sulphadimidine-containing tissue powders (400 vials each of muscle, liver and kidney) were prepared by orally dosing pigs with drug, producing lyophilized tissue powders and blending these with negative tissues from unmedicated animals to achieve target concentrations. Details of the production process, the stabilizing procedure developed and the analytical assessments of homogeneity and stability are given.

Animals↗

PubMedDate not supplied

Contamination of animal feedingstuffs with undeclared antimicrobial additives.

A study was carried out on 397 feedingstuffs and 11 premixes on which 161 (39.5%) were declared free of medication and 247 (60.5%) were medicated. These were subjected to analysis for the presence of antibiotics. Of the 247 medicated feeds 87 (35.2%) contained undeclared antimicrobials of which 59 (23.9%) were at a concentration sufficient to allow quantification by HPLC. Of the 161 unmedicated feeds 71 (44.1%) were shown to contain detectable antimicrobials of which 42 (26.1%) contained concentrations which could be quantified by HPLC. The most frequently identified contaminating antimicrobials were chlortetracycline (CTC) (15.2%), sulphonamides (6.9%), penicillin (3.4%) and ionophores (3.4%). Four samples (ionophores--3, sulphadimidine--1) contained therapeutic concentrations and one sample a supra-therapeutic concentration (monensin). The remainder were sub-therapeutic. All the contaminating concentrations of sulphadimidine detected were sufficient to cause violative tissue residues if fed to animals immediately prior to slaughter.

Animal Feed↗

PubMedDate not supplied

Evaluation of a modified EC Four Plate Method to detect antimicrobial drugs.

This paper describes a modification of the EC Four Plate Method based on microbial growth inhibition of Bacillus subtilis on agar medium at pH 6.0, 7.2 and 8.0 and Micrococcus luteus at pH 8.0 developed to cope with large numbers of samples. The method's performance was evaluated by determining the Minimum Inhibitory Concentrations of 66 commonly used drugs and determining the between-assay variation of antimicrobial control standards. The modified method proved particularly sensitive for beta-lactams, tetracyclines, quinolones, marcrolides and lincosamides and least sensitive for anticoccidials and nitrofurans. The pH 6.0 and 7.2 plates were more sensitive for 39 of the 66 antimicrobials (59%) whereas the two pH 8.0 plates (B. subtilis, M. luteus) were the most sensitive for 27 (41%). Muscle samples were taken from 1830 routine meat inspection investigations between 1994 and 1996. Of the 38 (2%) positive meat inspection carcasses, the following antimicrobials were confirmed above the MRL: penicillin G (10), oxytetracycline (16), sulphadimidine and sulphadiazine in combination (4) and chlortetracycline (1). The method as described is technically simple, cost effective, robust, suitable for large sample throughput and for frozen, thawed or fresh tissues. When all four plates are used the pattern of inhibition can reduce unnecessary confirmatory assays by indicating the antimicrobial group most likely to be present.

Animals↗

PubMedDate not supplied

Ureaplasmas in sheep.

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Animals↗