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Interpretive Summary: Trace amounts of antibiotics is detrimental to the health of weaned pigs

By: Anne Kamiya, MS

Although the administration of antibiotics in farm animals is now limited to treating active infections, trace amounts of antibiotics may still persist in surface water, groundwater, air, soil and dust. Exposure to trace amounts of antibiotics from the environment may have detrimental effects on young animals, negatively impacting their wellbeing and development.

The authors of this recent Journal of Animal Science study evaluated how trace amounts of antibiotics impacted the health and growth of weaned pigs. They accomplished this by challenging weaned pigs with a pathogenic strain of Escherichia coli bacteria and then feeding them diets with differing amounts of the antibiotic carbadox. Parameters to determine the health status of pigs included growth performance, intestinal health, diarrhea and immune system inflammatory markers. 

A total of 34 weaned pigs were orally infected with a pathogenic strain of E. coli and fed either a basal control diet with no antibiotics, trace amounts of antibiotics, or the typical therapeutic dose of antibiotics. Weight, blood and fecal samples were regularly evaluated. Intestinal tissue was collected at the end of the 11-day experiment. Nearly half of the pigs had to be euthanized within 5 days of infection. Pigs fed the control diet and trace antibiotics diet had a higher frequency of diarrhea and lower final body weight. Average daily gain and feed efficiency was lowest in the trace antibiotics group. Evaluation of fecal samples and intestinal tissue indicated that pigs fed trace amounts of antibiotics also had increased markers for inflammation.

Overall, the results of this small study suggest that trace amounts of antibiotics may be detrimental to the health of weaned pigs. Larger and more comprehensive studies looking at the impacts trace antibiotics have on young animal health and growth under non-infectious conditions is also justified.

The original article, Trace amounts of antibiotic exacerbated diarrhea and systemic inflammation of weaned pigs infected with a pathogenic Escherichia coli in Angus cattle, is available on the Journal of Animal Science website.