The use of antimicrobials dropped sharply between 2013 and 2017, according to an on-going survey of the U.S. turkey and broiler industries.
On March 30, 2021, Dr. Randall Singer, professor of epidemiology in the Department of Veterinary and Biomedical Sciences at the University of Minnesota and the founder and project lead at Mindwalk Consulting Group LLC, presented the results of an on-going research project to measure antimicrobial use in the poultry industry. His presentation was part of The Poultry Federation’s virtual Food Safety Conference which was held March 29-31, 2021.
Why measure antimicrobial use?
Singer said the key reason to monitor antimicrobial use is the supposed link between their use and antimicrobial resistance. The threat of drug-resistant pathogenic microbes being developed by antimicrobial use in animal agriculture is one of the underlying reasons for the rollback of antibiotic use in the poultry industry.
In 2017, the U.S. Department of Health and Human Services’ Food and Drug Administration (FDA) enacted the so-called Veterinary Feed Directive. At this time, the use of medically important antibiotics for growth promotion was eliminated due to the voluntary removal of growth promotion label claims on the medically important in-feed drugs by the pharmaceutical companies. The use of these drugs now requires veterinary oversight such as a prescription for in-feed and water-based antibiotics.
In theory, using antimicrobials can push microbes to adapt and develop resistance to the drugs – some of which are medically important in humans. However, the link between their use and development of resistance is not exactly clear, he said, and often depends upon a specific relationship between the drug and the microbe. Even if there is not a clear link, he said, its important to nevertheless use antimicrobials responsibly to preserve their efficacy.
Measuring antimicrobial use
To complicate the matter, there is no solid data on antimicrobial use in the United States. Rather, the FDA collects a so-called sales data report based on numbers supplied by drug manufacturers about how much antimicrobials they sold for use in animal agriculture. The agency then tries to estimate how much of that sale would have been used in different species. Therefore, the data in that report is not related to actual use.
Ideally, Singer said, data collected surrounding antimicrobial use would include the purpose of administration, the dosage, the route and the duration of the treatment, the number of birds being treated and the age at which the birds are treated.
That lead to the current project collecting data on on-farm antimicrobial use. Singer said the project’s goal is to develop and demonstrate an approach for collecting quantitative on-farm antimicrobial use data from the poultry industry. He said the collection program began as a pilot project funded by the U.S. Poultry and Egg Association (USPOULTRY) and is now a full project funded by the FDA and USPOULTRY. Industry participation is voluntary, and the participants are guaranteed data anonymity.
By the time the project reached 2017 data collection, industry participation was exceptional. He said 90% of all broiler production and 70% of all turkey production in the U.S. was represented in the survey. He said this is an important step in showing the responsibility of the integrators and that the data can be collected without the need for further regulation.
2013-2017 findings
The first round of use data, reflecting use between 2013 and 2017, is available now. The project continues onward, too. The available data for 2013-2017 reflected a significant decline in the use of antimicrobials in poultry production.
Between 2013 and 2017, the use of antimicrobials in the hatchery declined sharply for both broilers and turkeys. In 2013, 93% of chicks placed and 96% of poults placed received an antimicrobial in the hatchery. By 2017, those figures declined to 17% and 41%, respectively. Singer called that progress a huge accomplishment for the industry.
In-feed data suggested a decline in antimicrobial use through that avenue as well. Between 2013 and 2017, there were substantial declines in the use of tetracycline and virginiamycin, with the use of tetracycline nearly disappearing. Bacitracin in broiler feed, by comparison, was relatively steady.
Singer said this represents a shift from the use of medically important drugs – tetracycline and virginiamycin – toward perhaps not medically important drugs like bacitracin. That movement is a component of antimicrobial stewardship.
The trend in turkey was similar. Tetracycline use declined between 2013 and 2017 while bacitracin use was stable or possibly even increased slightly.
For water soluble antimicrobial use, Singer focused on the use of penicillin and lincomycin in turkeys. Those drugs are often used for treatment of gangrenous dermatitis, so they are important therapeutics used for treating sick birds. Even so, there was a decline recorded in the use of both drugs.
Further reduction in antibiotic use
With that in mind, Singer said the poultry industry should not be attempting to simply reduce antibiotic use further but should be focused on wise and prudent use of antibiotics.
He gave one example of how the system could be potentially gamed by reducing total antibiotic use through swapping one antimicrobial substance for a more potent one. This would yield a lower total amount of antimicrobial used but not actually change antimicrobial use.
With the example of gangrenous dermatitis prevention in the turkey industry in mind, he polled the survey group on how antibiotic use can be reduced further. They said there are only three real options: reduce the incidence of the disease, which isn’t realistic in the near term because there is no good intervention for it; stop treating the disease, which is unethical or switch to a stronger antimicrobial – from penicillin to lincomycin – that would reduce the amount to of antimicrobial used by nearly 14 times.
The poultry industry must get away from a mentality that all antimicrobials should be combined into a single number and the goal should be to reduce that total.
“For those of you who have customers demanding that you supply them with a single number of all your antimicrobial use, please push back and say, ‘No, I’m not going to give you that number because it is misleading and inaccurate,’” Singer said. “It doesn’t help us on the side of trying to use these antimicrobials to actually manage animal health.”
The future of the project
The next step in the data collection program is creating more granular data. The project needs to get more specific data on how many birds were treated each year, what they were treated with and why. More granular data will help understand more about the diseases, the dosage and the durations and aid in explaining whether disease incidence went up or just the use of the antimicrobial. More granular data will show how antimicrobials are being used.
Singer said the project is currently collecting data from the broiler and turkey industries reflecting results from 2017 to 2020 and is working on collecting data from the layer industry, too. So far, the data shows the key diseases the industry faces are necrotic enteritis, gangrenous dermatitis, airsacculitis and E. Coli. The picture of which antimicrobials are being used hasn’t changed.
