Environmental risks outweigh the benefits of zinc oxide to prevent diarrhea in pigs, the European Medicines Agency (EMA) has ruled.

The decision, made last week by the EMA’s Committee for Medicinal Products for Veterinary Use (CVMP), may bring the prospect closer of a ban on the use of products containing zinc oxide in pig feeds in the EU. The Committee recommended that future marketing authorizations for veterinary medicinal products containing zinc oxide are refused and that approvals of existing products containing this ingredient are withdrawn.

The matter had been referred to CVMP by France and the Netherlands because of concerns regarding a potential risk to the environment and an increased prevalence of antibiotic-resistant bacteria from the use of zinc oxide products.

The Committee reached a consensus that “the benefits of zinc oxide for the prevention of diarrhea in pigs do not outweigh the risks for the environment.”

On the development of antibiotic resistance, CVMP acknowledged the existence of a risk of co-selection for resistance associated with the use of zinc oxide, but added that the risk is not quantifiable.

Prospect of ban on zinc oxide concerns pig producers

In the UK, the National Pig Association (NPA) has expressed surprise and dismay at the CVMP’s recommendation to the national licensing authority, the Veterinary Medicines Directorate (VMD). VMD is a member of CVMP.

“Of course, the environmental risk of zinc oxide use is an important factor to consider but in all previous assessments, the CVMP has found the benefits of its use to outweigh the environmental risk, so you can understand our surprise at this apparent U-turn without clear explanation,” said NPA senior policy advisor, Georgina Crayford, in a letter to the VMD. “There also appears to be a stark omission from the CVMP’s assessment – that of the risk of development of resistance due to the increased use of antimicrobials that will likely occur should the ban on therapeutic use of zinc oxide proceed.”

Crayford added that a ban on the use of zinc oxide for oral treatment of pigs would also lead to more post-weaning diarrhea, which would negatively affect piglet welfare, and “seriously hamper the ability of the pig sector to reduce its use of antibiotics, as required by Government.”

Environmental assessment of zinc: 'No immediate concern'

The environmental risk of zinc in animal feeds had previously been considered by the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) of the European Food Safety Authority (EFSA).

In a report that covered a range of zinc-containing feed additives including the oxide published in April 2015, FEEDAP said, “The use of the zinc compounds under assessment does not pose an immediate concern for the agricultural soil compartment. However, there is a potential environmental concern related to drainage and the runoff of zinc to surface water, with acidic sandy soils being the most vulnerable.”

The Panel added that the adoption of the recently proposed maximum zinc contents in feeds would greatly reduce the risk to the environment from zinc-containing additives.

Following the suggestion, in July 2016, the European Union introduced new rules on the use of zinc in animal feeds, which included a lowering of the maximum level for fish feeds and calf milk replacers but kept the same inclusion as previously for pig feeds (150 mg/kg).