Betaine is the trimethyl derivate of the amino acid glycine and a widely used additive for animal diets. Due to its chemical structure various functions have been described for the betaine molecule:
In the metabolism free methyl groups are generated for several metabolic reactions, such as synthesis of creatine, carnitine and others. Both choline and betaine can be used as a methyl donor in the metabolism, although choline has to be converted into betaine in the mitochondria first. Methyl group metabolism is amongst others important in preventing fatty liver syndrome.
Betaine serves as an organic osmolyte, a substance which protects cells against osmotic stress, drought, high salinity and high temperature. Animals maintain an equilibrium in their cell structure by regulating movement of water in and out of the cells (osmoregulation). Betaine assists in maintaining this equilibrium and has proven efficiency in periods of heat stress.
Very positive effects are reported of betaine on feed digestibility and carcass quality. Betaine is used in diets for several animal species like broilers, turkeys, pigs and aqua feeds.