Scientific Opinion on the safety and efficacy of L-tryptophan produced by Escherichia coli CGMCC 7.59 for all animal species based on a dossier submitted by HELM AG on behalf of Meihua Holdings Co. Ltd
L-Tryptophan, technically pure, is a feed additive produced by a genetically modified Escherichia coli strain (CGMCC 7.59). The additive does not give rise to safety concerns regarding the genetic modifications of the production strain. The use of L-tryptophan produced by E. coli CGMCC 7.59 in feed is safe for non-ruminant target species when supplemented to diets in appropriate amounts. As the metabolites of L-tryptophan produced by ruminal bacteria may be toxic to the host animal, oral administration of unprotected L-tryptophan to ruminants should be avoided. The Panel on Additives and Products or substances used in Animal Feed (FEEDAP) has concerns about the safety of L-tryptophan for target species when administered via water for drinking. The composition of edible tissues and products of animal origin will not be changed by the use of the product L-tryptophan in animal nutrition when supplemented in appropriate amounts. No risks are expected for the consumer from the use of L-tryptophan, produced by E. coli CGMCC 7.59 as a feed additive, considering the purity of the additive (≥ 99.1 % L-tryptophan) and the low levels of 1,1′-ethylidene-bis-L-tryptophan (EBT) and 1-methyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid (MTCA) (< 10 mg/kg additive each). The product L-tryptophan, technically pure, is considered to be non-irritant to skin and eyes. In the absence of any data on sensitisation, the product should be considered a potential dermal sensitiser. The level of endotoxins present in the product and its dusting potential indicate a health risk for the user upon inhalation. The product under assessment does not pose any risk to the environment when supplemented to feed. The product L-tryptophan is regarded as an effective source of the amino acid L-tryptophan for all non-ruminant species. For the supplemental L-tryptophan to be as efficacious in ruminants as in non-ruminant species, it requires protection against degradation in the rumen.