L-Lysine base liquid, L-lysine monohydrochloride liquid, L-lysine monohydrochloride

In the current application authorisation is sought under Article 4 for L-lysine monohydrochloride, concentrated liquid L-lysine and concentrated liquid L-lysine monohydrochloride produced by fermentation with Escherichia coli NITE BP-02917, under the categories/functional groups 3(c) 'nutritional additives'/'amino acids, their salts and analogues' and 2(b) 'sensory additives'/flavouring compounds' according to Annex I of Regulation (EC) No 1831/2003. The authorisation is sought for all animal species. 

According to the Applicant, L-lysine monohydrochloride has a minimum purity (mass fraction on dry matter basis) of 99 % and a minimum L-lysine content of 78 % while the concentrated liquid L-lysine and the concentrated liquid L-lysine monohydrochloride have a minimum L-lysine content of 50 % and 22.4 %, respectively. 

When used as nutritional additive the solid form of the feed additive (L-lysine monohydrochloride) is intended to be added directly into feedingstuffs or through premixtures while the liquid forms (concentrated liquid L-lysine and concentrated liquid L-lysine monohydrochloride) are intended to be added directly into feedingstuffs. When used as sensory additive the three L-lysine forms are intended to be added directly into feedingstuffs and water for drinking. 

The Applicant did not propose any minimum or maximum content of L-lysine in feedingstuffs when used as nutritional additive, however a recommended inclusion level of 25 mg/kg feedingstuffs was proposed by the Applicant when used as sensory additive. 

For the quantification of lysine in the feed additive the Applicant proposed the ring-trial validated method EN ISO 17180:2013 based on ion-exchange chromatography coupled to visible or fluorescence detection (IEC-VIS/FLD). This standard method does not distinguish between the salts of amino acids and cannot differentiate between enantiomers. It applies for products containing more than 10 % of amino acid. The following performance characteristics are reported: a relative standard deviation for repeatability (RSDr) ranging from 0.7 to 1.7 % and a relative standard deviation for reproducibility (RSDR) ranging from 1.5 to 2.5 %. In addition, the EURL identified the "L-lysine monohydrochloride monograph" of the Food Chemical Codex (FCC) for the identification of L-lysine monohydrochloride in the feed additive. 

For the quantification of lysine in premixtures, feedingstuffs and water the Applicant proposed the ring-trial validated European Union method (Commission Regulation (EC) No 152/2009) based on IEC coupled with optical detection (IEC-VIS). This method, designed only for the analysis of amino acids in premixtures and feedingstuffs, does not distinguish between the salts and the amino acid enantiomers. The following performance characteristics were reported for the quantification of total lysine: RSDr ranging from 2.1 to 2.8 % and RSDR ranging from 3.0 to 6.7 %. Furthermore, as concluded in previous amino acids reports, the EURL also considers the IEC-VIS/FLD procedure described above as fit-for-purpose for the determination of lysine in water. 

Based on the performance characteristics available, the EURL recommends for official control (i) the "L-lysine monohydrochloride monograph" of the Food Chemical Codex (FCC) for the identification of L-lysine monohydrochloride in the feed additive (ii) the ring-trial validated method EN ISO 17180:2013 based on IEC-VIS/FLD to quantify free lysine in the feed additive and premixtures (containing more than 10 % lysine); (iii) the European Union method based on IEC-VIS for the quantification of lysine in premixtures and feedingstuffs; (for feedingstuffs only when used as nutritional additive) and (iv) the ion-exchange chromatography methods coupled with post-column derivatisation and optical detection (IEC-VIS/FLD) or coupled with post-column derivatisation and optical detection (IEC-VIS) for the quantification of lysine in water (only when used as nutritional additive). 

Further testing or validation of the methods to be performed through the consortium of National Reference Laboratories as specified by Article 10 (Commission Regulation (EC) No 378/2005), as last amended by Regulation (EU) 2015/1761) is not considered necessary.

Recommended Method

as of:

- Commission Implementing Regulation (EU) 2024/777:

For the identification of L-lysine monohydrochloride in the feed additives:

• Food Chemical Codex ‘L-lysine monohydrochloride monograph’

For the quantification of lysine in the feed additives and premixtures (containing more than 10 % lysine): 

• ion-exchange chromatography coupled with post-column derivatisation and optical detection (IEC-VIS/FLD) – EN ISO 17180

For the quantification of lysine in premixtures and compound feed:

• ion-exchange chromatography coupled with post-column derivatisation and optical detection (IEC-VIS), Regulation (EC) No 152/2009

For the quantification of lysine in water: 

• ion-exchange chromatography coupled with post-column derivatisation and optical detection (IEC-VIS/FLD); 

  or

• ion-exchange chromatography coupled with post-column derivatisation and optical detection (IEC-VIS)