Scientific Opinion on the safety and efficacy of L-threonine produced by Escherichia coli for all animal species, based on a dossier submitted by HELM AG on behalf of Global Bio-Chem Technology

The product L-threonine, technically pure, is a feed additive produced by fermentation with a genetically (GM) modified strain of Escherichia coli. L-Threonine is an essential amino acid for all animal species. It is commonly considered the second or third limiting amino acid in cereal-based diets for pigs and poultry, respectively. It is widely used in the feed industry to optimise the dietary protein. The amino acid L-threonine itself is considered safe for the target animals, the consumer and the environment. However, the genetic modification, including the presence/absence of recombinant DNA and of antibiotic resistance genes in the product, is insufficiently characterised. Consequently, the FEEDAP Panel cannot conclude on the safety of the L-threonine produced by fermentation with this recombinant strain of E. coli for target animals, consumers, users and the environment. Regardless of the assessment of the genetic modification, the FEEDAP Panel has concerns about the safety of amino acids, including L-threonine, for target species when administered via water for drinking. From results provided, it is concluded that there is no concern for users in respect of respiratory toxicity or skin or eye irritancy. In the absence of any data on sensitisation it must be concluded that the product may have potential to be a dermal sensitiser. The amino acid L-threonine itself does not pose any risk to the environment. The product L-threonine is an efficacious source of supplemented amino acid to maintain or restore the adequate balance of dietary amino acids for all non-ruminant species. Supplemental threonine is mainly degraded by ruminal microbiota, if not given in a protected form.