Poultry vet defends use of ionophores to control coccidiosis

A poultry vet has defended the use of ionophores to control coccidiosis in broilers, saying that the substances are not antibiotics, as some define them.

“Ionophores are antiparasitics, they are never used in human medicine,” according to James Horner, who is a technical consultant at pharmaceutical outfit Elanco.

“They have been trialled in some cancer therapies, but, ultimately, they are not used.”

These complicated substances cannot be synthesised. Instead, ionophores are made by fermenting streptomyces bacteria, and there are currently five to six that are usually used commercially, with more than 20 others that are not yet in commercial use.

See also: Advice on flies, BVD, coccidiosis and mastitis

But they are being “muddled up” in the antibiotics debate, Dr Horner told the recent Poultry Meat Conference.

Regulation and definition

The reason predates the current scrutiny over antibiotics in farm animals, suggested Dr Horner, when there was little regulation in their use in farming to promote growth rates.

Coccidiostats’ usefulness to poultry production first emerged in the late 1960s, and Europe recognised that coccidiosis was a ubiquitous presence in poultry production and that, as treatments were added to feed, they were regulated as such.

In contrast, in the US, ionophores were classified as animal-only antibiotics and removed from use in farms producing “no antibiotics ever” chicken when it emerged as a new category of production.

The result, explained Dr Horner, is that in the US, the use of critically important antibiotics has increased, cost of production is up and welfare outcomes are poorer.

“A lot of those problems have come from disturbance through mismanagement of the microbiome, because of poor coccidiosis control.”

In contrast, in Europe, ionophores are currently classified and regulated under feed additive legislation, which is regularly reviewed.

Ionophores under review

When they were last assessed in 2008, ionophores were not considered to contribute to antibiotic resistance, so were not reclassified.

Another review is under way, and pressure is mounting from some groups to reconsider their classification.

At present, coccidials can be administered prophylactically, but if they were to require a veterinary prescription when a problem was identified, Dr Horner said, it could delay treatment and potentially end up with more severe interventions with antibiotics.

“Effective control of coccidiosis through the use of ionophores as an anti-parasitic minimises that impact on intestinal integrity,” he added.

“But most importantly, by stabilising intestinal integrity, it maintains a solid microbiome – and with that, you can optimise health and welfare.”

Latest figures reveal spike in antibiotics use last year

In 2018, British poultrymeat producers used 12.4% more antibiotics than the previous year, a new report reveals.

The increase was primarily down to more broilers being treated, lifting some 25% from 9.9mg/pcu (miligrams per population correction unit) to 12.4mg/pcu.

The British Poultry Council (BPC), which monitors and reports on antibiotics use for the poultrymeat sector, said that seasonal illnesses through the winter and spring of 2018 accounted for the lift.

“Having reached a low level of usage, it is inevitable that our annual figure will fluctuate up and down in response to the challenges we face during that period,” the BPC said.

“What is key is that we continue to be open and honest about the reasons behind these fluctuations and what we are doing to mitigate them in the future.”

Since 2012, the UK poultry industry has recorded an 82.2% total decline in antibiotics use and a 90% reduction in the use of antibiotics considered critical to human health.

Graeme Dear, the BPC’s chairman, said the sector remained at the forefront of international efforts to keep antibiotics effective.

But he cautioned against removing them entirely from farming

“Zero use is neither ethical nor sustainable as it goes against a farmer’s duty to address any health and welfare issues.”

Coilin Nunan, from the Alliance to Save Our Antibiotics, said the overall reduction was welcome, but added: “What we now appear to be seeing are the limitations of the BPC’s approach, which has not put sufficient emphasis on improving husbandry and animal health

“We know that if more resilient, slower-growing breeds of chicken are used, and if stocking densities are reduced, antibiotics use can be cut far more as disease outbreaks are less likely.”