“Lysine supports immune function and is the most important essential amino acid in horses.” – Jack Grogan, CN
Essential Amino acids must be provided in the horse’s diet because they can not be synthesized in the body.
Lysine is also commonly considered a limiting amino acid – an essential amino acid that is most likely to be present in the diet in the lowest amount. If limiting amino acid amounts are not adequate, protein synthesis won’t be able to proceed normally. While extreme Lysine deficiencies are highly unlikely with common diets, even small deficiencies can make a difference between so-so and good muscling. Recent research has confirmed that Lysine is an important limiting amino acid for growth. Diets that contain at least 4.3% of their crude protein as Lysine support the same weight gains/growth as lower levels of total crude protein because of more efficient utilization of the other amino acids in the body. – Dr. Eleanor Kellon VMD
Lysine is the only amino acid with an NRC requirement and is especially important in young growing horses, pregnant and lactating mares and senior horses.