Lysine

Lysine is one of 20 amino acids that make up all body proteins. Lysine is one of the essential amino acids and must be supplied through the diet. If there is too little lysine in the ration, the body cannot, for example, build muscle tissue to its full extent. In this case, the amino acid lysine is said to have a limiting effect. Lysine is generally regarded as the first limiting essential amino acid, as its levels in feed are usually low.

In general, horses can only make use of amino acids that are digestible in the small intestine (abbreviated as pcv). The maintenance requirement for small intestine digestible lysine (pcvLys) for a warmblood is 13 to 15 grams per day (GfE, 2014). Late-cut hay with values of around 1.4 g pcvLys/kg can usually only cover this maintenance requirement. A deficiency becomes noticeable in horses with an increased requirement (e.g. brood mares, weanling foals, young horses in training, senior horses or (sport) horses in muscle-building training) through loss of muscle body substance or poor muscle development.

Grass, soy extraction meal or brewer’s yeast, on the other hand, provide high amounts of pcvLys. Speciality feeds containing pure, crystalline L-lysine are 100% digestible in the small intestine and are the most metabolically gentle of all protein feeds. This L-lysine is contained, for example, in marstall Amino-Muskel.