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. 2025 Oct 9;23(10):e9687.
doi: 10.2903/j.efsa.2025.9687. eCollection 2025 Oct.

Safety and efficacy of a feed additive consisting of L-isoleucine produced with Escherichia coli CCTCC M 20231916 for all animal species (Kempex Holland B.V.)

EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP); Roberto Edoardo Villa, Giovanna Azimonti, Eleftherios Bonos, Henrik Christensen, Mojca Durjava, Birgit Dusemund, Ronette Gehring, Boet Glandorf, Maryline Kouba, Marta López-Alonso, Francesca Marcon, Carlo Nebbia, Alena Pechová, Miguel Prieto-Maradona, Ilen Röhe, Katerina Theodoridou, Montserrat Anguita, Nicole Bozzi Cionci, Matteo L Innocenti, Maria Kolona, Jordi Tarrés Call

Safety and efficacy of a feed additive consisting of L-isoleucine produced with Escherichia coli CCTCC M 20231916 for all animal species (Kempex Holland B.V.)

EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) et al. EFSA J. .

Abstract

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of L-isoleucine produced with Escherichia coli CCTCC M 20231916 as a nutritional feed additive for all animal species. The production strain E. coli CCTCC M 20231916 is genetically modified. No viable cells nor DNA of the production strain are detected in the final product. Therefore, the additive does not pose any safety concern regarding the production strain. The use of L-isoleucine produced by fermentation with E. coli CCTCC M 20231916 in feed is safe for the target species when supplemented in appropriate amounts to the diet according to their nutritional needs. The FEEDAP Panel has concerns about the use of L-isoleucine in water for drinking. The use of L-isoleucine produced by fermentation with E. coli CCTCC M 20231916 in animal nutrition is considered safe for consumers and the environment. As regards the safety for the user, the FEEDAP Panel cannot conclude on the potential of the additive to be irritant to skin and/or eyes and to be a potential skin sensitiser. The feed additive consisting of L-isoleucine produced by fermentation with E. coli CCTCC M 20231916 is regarded as an effective source of the amino acid L-isoleucine for all non-ruminant species. For the supplemental L-isoleucine to be as efficacious in ruminants as in non-ruminant species, it requires protection against degradation in the rumen.

Keywords: Escherichia coli CCTCC M 20231916; L‐isoleucine; amino acids; efficacy; nutritional additives; safety.

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Figures

FIGURE 1
FIGURE 1
Structural formula of L‐isoleucine.
See this image and copyright information in PMC

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