Abstract
One of the well known biological functions of betaine is that of a methyl donor. Therefore, betaine may partly replace choline and methionine in the diet. Another widely documented role of betaine is to restore and maintain the osmotic balance. As an organic osmotic compound, betaine regulates the water balance, thus exerting a stabilizing influence on tissue metabolism, particularly within the digestive tract. As a donor of methyl groups necessary for various reactions in the body, betaine is indirectly involved in lipid metabolism. Due to its metabolic functions, betaine is also believed to play a significant role in energy metabolism in pigs. Of particular note are the results of experiments in which a positive effect of betaine supplementation was observed as the energy content of the diet was decreased.