|ONG, SAY KEE|
Submitted to: Water Environment Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/28/2004
Publication Date: 1/15/2005
Citation: Kolz, A., Moorman, T.B., Ong, S., Scoggin, K.D., Douglass, E.A. 2005. Degradation and metabolite production of tylosin in anaerobic and aerobic swine manure lagoons. Water Environment Research. 77(1):49-56.
Interpretive Summary: Antibiotics have been detected in rivers and streams, and confined animal feeding operations (CAFOs) are thought to be one source. Tylosin is an antibiotic commonly used in swine production and this research examined what happens to tylosin in swine manure lagoons. Immediately after tylosin addition to lagoon samples it is rapidly dissipated, except under anaerobic conditions where 5 to 15% of the added tylosin persisted for long periods. Extensive binding of tylosin to the solid manure particles was observed. The results indicate that most tylosin entering the lagoon system will be degraded or bound, but since anaerobic lagoons are common some tylosin will enter farmers fields when the lagoon slurries are applied to the soil. These findings add to our knowledge of antibiotics in the environment and may be useful in design of manure treatment systems.
Technical Abstract: Watershed contamination from antibiotics is becoming a critical issue due to increased numbers of confined animal feeding operations (CAFOs) and antibiotics use in animal production. To understand the fate of tylosin in manure before it is land applied, degradation in manure lagoon slurries at 22 degrees C was studied. Tylosin disappearance followed a biphasic pattern, where rapid initial loss was followed by a slow phase. The 90% disappearance times for tylosin A, D and B in anaerobically incubated slurries were 30 to 130 hours. Aerating slurries reduced the 90% disappearance times to between 12 and 26 hours. Biodegradation and abiotic degradation occur, but strong sorption to slurry solids was likely the primary mechanism of tylosin disappearance. Dihydrodesmycosin and an unknown degradate with molecular mass of 933.5 amu were detected. Residual tylosin remained in slurry after 8 months incubation, indicating that degradation in lagoons is incomplete and that residues will enter agricultural fields.