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

The product L-tryptophan is a feed additive produced by fermentation with a genetically modified (GM) strain of Escherichia coli. The amino acid L-tryptophan 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-tryptophan 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 on the use of unprotected forms of L-tryptophan in ruminants, and on the safety of the amino acid L-tryptophan for target species when administered simultaneously via water for drinking. The product has been shown to be non-irritant to skin and eyes, and non-toxic by inhalation but should be considered as a potential dermal sensitizer. The amino acid L-tryptophan itself does not pose any risk for the environment. The additive L-tryptophan is regarded as an effective source of L-tryptophan for all non-ruminant species. Supplemental L-tryptophan is mainly degraded by ruminal microbiota, if not given in a protected form.