EU Sets New Standards for L-Lysine Testing in Animal Feed

New recommendations have been issued for the analysis of L-lysine in animal feed. The European Union Reference Laboratory (EURL) has proposed specific methods to measure lysine content in various feed products. These guidelines cover additives, premixtures, compound feed, and drinking water for livestock.

The authorisation request includes L-lysine monohydrochloride, L-lysine in concentrated liquid form, and L-lysine produced via fermentation using Corynebacterium glutamicum strains KCCM 80368 or KCCM 80479. These additives are intended for all animal species under two functional groups: nutritional additives (amino acids and their salts) and sensory additives (flavouring compounds).

The EURL recommends different testing methods depending on the product. For premixtures and compound feed, it advises using the EU’s ring-trial validated IEC-VIS method. When measuring free lysine in premixtures with over 10% lysine content, the EN ISO 17180 method is preferred. For lysine in drinking water, the IEC-VIS-based EU method is again suggested. The applicant has also proposed a modified version of the EU method for analysing lysine in the additives themselves. To confirm the identity of L-lysine monohydrochloride, the EURL points to the *Food Chemical Codex* monograph. The feed additives must contain at least 78% L-lysine (dry matter) for solid forms and 50% for the liquid base. When used as a flavouring, the maximum allowed concentration in compound feed is 25 mg/kg.

These recommendations provide clear testing standards for L-lysine in animal nutrition. The methods ensure accurate measurement across different feed types and water. The proposed limits and identification procedures will help regulate the safe and effective use of these additives in livestock diets.