16 broiler ducks were fed with the therapeutical dose (15 mg/kg of fee
d) of avoparcin, a growth promoter antibiotic (Avotan(R) 10% premix, A
merican Cyanamid, USA) during 28 days. Eight ducks served as controls
(Table 1). Three ducks each were exsanguinated on the last day of feed
ing experiment and 3 days later.Residue content of muscle, liver, kidn
ey and adipose tissue samples collected from the exsanguinated birds w
as determined by a microbiological (B. subtilis BGA strain, detection
limit 33.34 mug/kg) and RIA methods (detection limit 1-10 mug/kg). Mus
cle, liver, kidney and adipose tissue samples of continuously fed duck
s did not show any antimicrobial activity. Residue content of muscle a
nd liver samples was 1 mug/kg, that of kidneys and adipose tissue was
lower than 13.2 mug/kg and 8.1 mug/kg, respectively on the last day of
avoparcin feeding (Table 2).According to the present day toxicologica
l knowledge, as in case of other animal species (pig, broiler chickens
, turkeys, dairy cattle). it is not necessary to determine a withdrawa
l period in ducks after avoparcin feeding.