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Proposed amended livestock feed ingredient – L-Threonine: Closed Consultation

Current status: Closed

This consultation ran from February 21, 2024 to March 22, 2024

About the consultation

The Canadian Food Inspection Agency (CFIA) was seeking comments on the following amended single ingredient feed (SIF) description for L-threonine.


The Feeds Regulations require a proponent to submit a pre-market application for SIFs that are new, have been modified such that they differ from an approved SIF, or are for a new purpose. The CFIA evaluates the information in the application to establish that the SIF is safe, effective, and labelled correctly.

Approved SIFs are currently listed and defined in Schedules IV and V of the Feeds Regulations, with appropriate guarantees, standards, and labelling requirements. The CFIA will be transitioning to the Canadian Feed Ingredients Table (CFIT) that will be incorporated by reference into the proposed Feeds Regulations, 2024 when they come into effect. In preparation for this new approach, the CFIA is consulting on new or amended SIFs so they can be added to the CFIT once it comes into effect. More information on this is available in the Notice to industry: Consultations on new or amended single ingredient feed descriptions.

About the evaluation

The CFIA's Animal Feed Program (AFP) has identified that the current description for L-threonine does not have the correct nomenclature, and therefore the existing description is to be amended with the correct chemical name.

The CFIA recommends the description for L-threonine be amended to reflect the current chemical name, and the amended SIF description replace the current SIF description in the CFIT accordingly.

Amended SIF description

The CFIA intends to amend the existing SIF description for L-threonine under subclass 5.1.2 (Amino acids excluding those from fermentation processes) of Class 5 (Nutritional ingredients) in part 1 of the CFIT. The description is to be amended to include the correct chemical name. The amended description is:


is the product that contains a minimum of 95% (2S,3R)-2-amino-3-hydroxybutanoic acid, and having the CAS# 72-19-5.

It shall be labelled with a guarantee for minimum percent L-threonine.

Additional information

During the drafting of the description for L-threonine from fermentation process, the CFIA's AFP identified that the chemical name in the existing description for L-threonine was outdated. The existing description for L-threonine uses the chemical name alpha-epsilon-2-amino-3-hydroxybutyric acid. This will be amended to (2S,3R)-2-amino-3-hydroxybutanoic acid. This is just an update to the name to reflect current naming conventions and does not change the SIF or its intended purpose.

The purpose of this SIF is still as a supplemental source of the amino acid, L-threonine, for all livestock species.

Who was the focus of this consultation

Animal feed stakeholders, including:

All comments are welcome from industry, governments, the public, or other organizations or individuals.

How to participate

The CFIA was seeking feedback on the amended description for L-threonine.

Stakeholders were encouraged to share comments if there was:

The CFIA evaluators will review scientific questions or information for consideration in the evaluation. They will also evaluate non-scientific input and explore appropriate ways of addressing it.

Comments can be sent by email to the Animal Feed Program (AFP) at Please use "L-threonine" in the subject line of the email. The CFIA was asking for comments and feedback by March 22, 2024, 30 days from the date of this posting.

Next steps

The CFIA will review all of the comments received, if no significant scientifically valid concerns are raised, the CFIA will finalize the amended description for L-threonine.

If significant concerns are raised, the CFIA will evaluate the additional information. A what we heard report that summarizes the feedback received will be published.

This amended SIF description will be added to the CFIT at the next update, following publication of the proposed Feeds Regulations, 2024.

Related information

Contact us

Animal Feed Program (AFP)
Canadian Food Inspection Agency
59 Camelot Drive
Ottawa, Ontario K1A 0Y9

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