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Official Journal EN
of the European Union L series
2026/1117 27.5.2026
COMMISSION IMPLEMENTING REGULATION(EU) 2026/1117
of 26 May 2026
concerning the authorisation of L-isoleucine produced with Escherichia coliCCTCC M 20231916 as a
feed additive for all animal species
(Text with EEA relevance)
THE EUROPEAN COMMISSION,
Having regard to the Treaty on the Functioning of the European Union,
Having regard to Regulation (EC) No 1831/2003 of the European Parliament and of the Council of 22 September 2003 on
additives for use in animal nutrition(1), and in particular Article 9(2) thereof,
Whereas:
(1) Regulation (EC) No 1831/2003 provides for the authorisation of additives for use in animal nutrition and for the
grounds and procedures for granting such an authorisation.
(2) In accordance with Article 7 of Regulation (EC) No 1831/2003, an application was submitted for the authorisation of
L-isoleucine produced with Escherichia coli CCTCC M 20231916. That application was accompanied by the
particulars and documents required under Article 7(3) of Regulation (EC) No 1831/2003.
(3) The application concerns the authorisation of L-isoleucine produced with Escherichia coliCCTCC M 20231916 as a
feed additive for use in feed and in water for drinking for all animal species, requesting that additive to be classified
in the additive category ‘nutritional additives’ and in the functional group ‘amino acids, their salts and analogues’.
(4) The European Food Safety Authority (‘the Authority’) concluded in its opinion of 17 September 2025(2)that the use
of L-isoleucine produced with Escherichia 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. However, due to the risk of
nutritional imbalances and hygienic reasons, the Authority has concerns on the of use L-isoleucine in water for
drinking. The Authority also concluded that the use of L-isoleucine produced with Escherichia coli CCTCC M
20231916 in animal nutrition is safe for the consumers and the environment. In the absence of data, it could not
conclude on the potential of the additive to be irritant to skin and/or eyes and to be a potential skin sensitiser but
identified an inhalation risk to endotoxins for the users of the additive. The Authority further concluded that the
substance is regarded as an efficacious source of the amino acid L-isoleucine for non-ruminant nutrition. For the
supplemental L-isoleucine to be as efficacious in ruminants as in non-ruminant species, it requires protection against
degradation in the rumen. The Authority did not consider that there is a need for specific requirements of post-
market monitoring. It also verified the report on the method of analysis of the feed additive in feed submitted by the
Reference Laboratory set up by Regulation (EC) No 1831/2003.
(1) OJ L 268, 18.10.2003, p. 29, ELI: http://data.europa.eu/eli/reg/2003/1831/oj.
(2) EFSA Journal2025, 23(10):e9687, https://doi.org/10.2903/j.efsa.2025.9687.
ELI: http://data.europa.eu/eli/reg_impl/2026/1117/oj 1/4EN
OJ L, 27.5.2026
(5) In view of the above, the Commission considers that L-isoleucine produced with Escherichia coliCCTCC M 20231916
satisfies the conditions provided for in Article 5 of Regulation (EC) No 1831/2003. Accordingly, the use of that
substance as a feed additive should be authorised. The Commission considers that possible hygiene risks related to
the use of this amino acid in water for drinking, are to be addressed by feed business operators under their
obligations to ensure compliance with the relevant hygiene requirements laid down in Regulation (EC) No 183/2005
of the European Parliament and of the Council(3)laying down requirements for feed hygiene. When fed to ruminants,
L-isoleucine produced with Escherichia coli CCTCC M 20231916 should be protected against degradation in the
rumen. It is appropriate to alert the user to take into account the dietary supply with all the essential and
conditionally essential amino acids, in particular in the case of supplementation with L-isoleucine via water for
drinking. In addition, the Commission considers that appropriate protective measures should be taken to prevent
adverse effects on the health of the users of the additive.
(6) The measures provided for in this Regulation are in accordance with the opinion of the Standing Committee on
Plants, Animals, Food and Feed,
HAS ADOPTED THIS REGULATION:
Article 1
Authorisation
The substance specified in the Annex, belonging to the additive category ‘nutritional additives’ and to the functional group
‘amino acids, their salts and analogues’, is authorised as an additive in animal nutrition, subject to the conditions laid down
in that Annex.
Article 2
Entry into force
This Regulation shall enter into force on the twentieth day following that of its publication in the Official Journal of the
European Union.
This Regulation shall be binding in its entirety and directly applicable in all Member States.
Done at Brussels, 26 May 2026.
For the Commission
The President
Ursula VON DER LEYEN
(3) Regulation (EC) No 183/2005 of the European Parliament and of the Council of 12 January 2005 laying down requirements for feed
hygiene (OJ L 35, 8.2.2005, p. 1, ELI: http://data.europa.eu/eli/reg/2005/183/oj).
2/4 ELI: http://data.europa.eu/eli/reg_impl/2026/1117/ojANNEX
Minimum Maximum
Identification Species or content content
Name of the Composition, chemical formula, End of period of
number of the category of Maximum age Other provisions
additive description, analytical method authorisation
additive animal mg/kg of complete feed with
12 % moisture content
Category: nutritional additives. Functional group: amino acids, their salts and analogues
3c384i L-isoleucine Additive composition All animal — — — 1. In the directions for use of 16 June 2036
L-isoleucine species the additive and
premixtures, the storage
Solid form conditions and the
stability to heat treatment
Characterisation of the active substance
and in water for drinking
L-isoleucine ≥ 90 % (on a dry matter
shall be indicated.
basis) produced with Escherichia coli
CCTCC M 20231916
2. The additive may be used
IUPAC name: (2S,3S)-2-amino- via water for drinking.
3-methylpentanoic acid
3. Feed business operators
Chemical formula: C H NO
6 13 2 shall ensure that
CAS number: 73-32-5 L-isoleucine is rumen
protected, when fed to
Analytical method(1)
ruminants.
For the identification of L-isoleucine in
the feed additive: 4. The moisture content
— Food Chemical Codex ‘L-isoleucine shall be indicated on the
monograph’; label of the additive.
For the determination of isoleucine in
the feed additive: 5. The labelling of the
— Ion-exchange chromatography additive and premixtures
coupled to post-column shall indicate the
derivatisation and optical detection following: ‘The
(IEC-VIS/FLD or IEC-VIS); supplementation with
L-isoleucine, in particular
For the determination of isoleucine in via water for drinking,
premixtures: shall take into account all
— Ion-exchange chromatography essential and
coupled to post-column conditionally essential
derivatisation and optical detection amino acids in order to
(IEC-VIS/FLD) or avoid nutritional
imbalances’.
ELI:
http://data.europa.eu/eli/reg_impl/2026/1117/oj
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ENMinimum Maximum
Identification Species or content content
Name of the Composition, chemical formula, End of period of
number of the category of Maximum age Other provisions
additive description, analytical method authorisation
additive animal mg/kg of complete feed with
12 % moisture content
— Ion-exchange chromatography 6. The endotoxin content of
coupled to post-column the additive and its
derivatisation and optical detection dusting potential shall
(IEC-VIS), Commission Regulation ensure a maximal
(EC) No 152/2009(2); endotoxin exposure of
1 600 IU endotoxins/m3
For the determination of isoleucine in
air(3).
compound feed:
— Ion-exchange chromatography
7. For users of the additive
coupled to post-column
and premixtures, feed
derivatisation and optical detection
business operators shall
(IEC-VIS), Regulation (EC)
establish operational
No 152/2009;
procedures and
For the determination of isoleucine in organisational measures
water for drinking: to address potential risks
— Ion-exchange chromatography resulting from their use.
coupled to post-column Where those risks cannot
derivatisation and optical detection be eliminated by such
(IEC-VIS). procedures and
measures, the additive
and premixtures shall be
used with personal skin,
eye and breathing
protective equipment.
(1) Details of the analytical methods are available at the following address of the Reference Laboratory: https://joint-research-centre.ec.europa.eu/eurl-fa-eurl-feed-additives/eurl-fa-authorisation/eurl-fa-
evaluation-reports_en.
(2) Commission Regulation (EC) No 152/2009 of 27 January 2009 laying down the methods of sampling and analysis for the official control of feed (OJ L 54, 26.2.2009, p. 1, ELI: http://data.europa.eu/eli/reg/
2009/152/oj).
(3) Exposure calculated based on the endotoxin level and the dusting potential of the additive according to the method used by EFSA (EFSA Journal 2018;16(10):5458); analytical method: European
Pharmacopoeia 2.6.14. (bacterial endotoxins).
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