Manitoba Cooperator: Antibiotics manure risk requires a rethink
A University of Manitoba research paper may upend the way environmental scientists consider the issue of residual antibiotics in manure.
They’re a cause of concern because when they’re fed to animals, a lot of the antibiotics pass right through the animal and into the manure. Scientists have worried that could promote antibiotic resistance.
“Often, 90 per cent or more of the antibiotic is excreted, according to previous studies,” says Francis Zvomuya, a researcher at the university.
Lead author Inoka D. Amarakoon, a PhD candidate, looked at those previous studies and realized that those researchers were fortifying manure with antibiotics and then tracking their breakdown. In the real world, when they pass through the gut of an animal, they undergo chemical and biological changes.
The Manitoba researchers fed combinations of antibiotics to steers and collected their droppings to compare to a control herd’s droppings that were fortified.
Results were mixed. For some antibiotics, the excreted antibiotics degraded more quickly. Other antibiotics degraded faster when added directly to manure. Amarakoon said such mixed findings were to be expected when looking at different products….