Study of the depletion of tylosin residues in honey extracted from treated honeybee (Apis mellifera) colonies and the effect of the shook swarm procedure.

Bee colonies were dosed with tylosin tartrate 1.1 g per hive (single dose in sucrose solution) and samples of honey were then collected at intervals over a 20-week period. The samples were analysed for tylosin A and desmycosin (tylosin B) using LC-MS/MS. The mean concentration of tylosin A in the honey (pooled results) 3 days after dosing was 17??g/g, declining to 0.9??g/g after 140 days. The mean concentration of desmycosin was 2.3 ?g/g, 3 days after dosing declining to 1.1??g/g after 140 days. The shook swarm procedure was investigated and resulted in a tylosin A concentration in brood honey of 10??g/g, 3 days after dosing declining to 0.02??g/g, 140 days after dosing. A corresponding decrease in the mean concentrations of desmycosin in brood honey, 1.1??g/g, 3 days after dosing to 0.03??g/g, 140 days after dosing also was observed. Tylosin A depletes to desmycosin in honey and can still be detected 238 days after dosing. Thus a more accurate residue definition is the sum of tylosin A and desmycosin. [ABSTRACT FROM AUTHOR]