Detection of maduramycin residues in the tissues of chickens and pheasants by the screening test for antibiotic residues (STAR)

Maduramycin is a coccidiostat authorized as a feed additive in poultry. Council Directive 96/23/EC stipulates that monitoring of foods of animal origin for residues of coccidiostats is mandatory. The aim of the present study was to evaluate the STAR for the screening of maduramycin residues in the tissues of broiler chickens and pheasants. Both animal species were supplied feed medicated with Cygro l% premix according to recommendations for use (5 mg kg-1 of complete feed). The residues were investigated for a period of 7 days: day 0 (the last day of the administration of maduramycin), days 1-5 (the days of the withdrawal period) and day 6 (the first day after elapse of the withdrawal period). According to STAR the positivity of the sample (the presence of residues of antibacterial substances) is indicated by a zone of inhibition exceeding 2 or 4 mm in width, depending on the test organism. Maduramycin residues were detected only on the plates seeded with the test organism Bacillus stearothermophilus var. calidolactis ATCC 10149. The results showed that there was higher potential for the presence of maduramycin residues in broiler chickens than in pheasants. All chicken tissues (muscle/thigh and breast/gizzard, liver, heart, kidneys, spleen, lungs) were positive for maduramycin (inhibition zones epsilon 4 mm) not only throughout the withdrawal period, but also even 5 days after elapse of the withdrawal period. In the case of pheasants the positive results were detected in the gizzard, liver, heart, kidneys, spleen and lungs. On day 5 of the withdrawal period no positive results were detected; however, on day 6 the heart and spleen were positive again.