EFSA FEEDAP — L-tryptophan (C. glutamicum KCCM 80346, GM) for all animal species
Source: EFSA FEEDAP scientific opinion, EFSA Journal 2025;23(12):e9795 (DOI 10.2903/j.efsa.2025.9795), retrieved 2026-08-06 via Europe PMC OA full-text XML. Paraphrase of an EFSA opinion that the source XML tags CC-BY-ND; per project COPYRIGHT_POLICY only facts/numbers/proper-nouns are quoted verbatim, sentences rewritten.
Editorial context (read this before using the data point)
This is the EFSA FEEDAP jurisdiction on the amino-acid feed additive C. glutamicum KCCM 80346 — one of four amino-acid safety opinions in this batch. Read with the efsa nutrient endpoints and AAFCO/FEDIAF amino-acid provisions.
Key findings (paraphrase; numbers and proper nouns verbatim from source)
- L-tryptophan is produced using the genetically modified strain *C. glutamicum* KCCM 80346; characterised up to 94.9%, so conclusions apply only to that manufacturing process.
- Its use in animal nutrition is considered safe for all animal species and safe for the consumer and for the environment.
- There may be a risk in ruminants (pulmonary injury) when unprotected tryptophan is used, linked to increased production of the pneumotoxic metabolite 3-methylindole (skatole).
- For user safety it is not irritant to skin or eyes but should be considered a skin and respiratory sensitiser; inhalation and dermal exposure are a risk.
- It is an effective source of the essential amino acid L-tryptophan for all animal species; to match non-ruminant efficacy in ruminants it should be protected from ruminal degradation.
Pet-food relevance
L-tryptophan is an essential amino acid in cats and dogs. The broad 'safe for all animal species' conclusion is the headline; the ruminant pulmonary-injury caveat is the key species-specific limitation. The ~5% unidentified fraction (fermentation residues) is the stated residual uncertainty.
Scope note / honest gap
Paraphrase of an EFSA opinion; source XML licence tag was CC-BY-ND, so this topic quotes only data points verbatim and rewrites prose. Full genotoxicity and sub-chronic study details are not reproduced.