Scientific Opinion on the safety and efficacy of L-threonine produced by Escherichia coli strains NRRL B-30843, DSM 26131, KCCM11133P or DSM 25085 for all animal species based on a dossier submitted by AMAC EEIG
This opinion concerns L-threonine as a feed additive produced by four different strains derived from Escherichia coli K-12. Three strains are genetically modified (GM): NRRL B-30843, KCCM11133P and DSM 26131. L-Threonine produced by E. coli DSM 26131 could not be assessed because of the insufficient molecular characterisation of the genetic modification, and the lack of data on both the absence of the production strain and its recombinant DNA from the final product. No safety concerns were found in the products related to the genetic modification of the other GM strains or to antibiotic resistance of the producer strains. L-Threonine products made by fermentation using E. coli strains NRRL B-30843, KCCM11133P and DSM 25085 are free of the production strain and have a high purity (≥ 98.8 %). L-Threonine, technically pure, produced by E. coli strains NRRL B-30843, KCCM11133P and DSM 25085 is safe for the target animals when used in appropriate amounts to supplement threonine-deficient feeds, for the consumer of animal products and for the environment. The FEEDAP Panel considers that L-threonine produced by E. coli strains NRRL B-30843, KCCM11133P or DSM 25085 is not an irritant to eyes and skin, and is not a skin sensitiser. There is no risk from inhalation of L-threonine, but concerns may arise from the content of endotoxins in the products. These L-threonine products are considered an efficacious source of the amino acid L-threonine for all animal species. For L-threonine to be as efficacious in ruminants as in non-ruminant species, it requires protection against degradation in the rumen. The Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) has concerns regarding the safety of the simultaneous oral administration of L-threonine via water for drinking and feed.