Betaine is ubiquitous in animals, and beet is the plant with the most betaine. In recent years, the application of betaine in livestock and poultry industry has received more and more attention. This is because betaine can provide active methyl group in the metabolism of biological organism, form methyltransferase with cysteine, and participate in methyl reaction, so it is called "life methylation agent". In addition, choline chloride and methionine have the function of providing active methyl. However, as a non-toxic, pollution-free and residue free new nutrient redistribution agent, betaine has overcome β-– Adrenergic agonists and other nutrient redistribution agents cause a series of drawbacks, such as high stress, serious residue and meat quality decline.

The chemical name of betaine is trimethylglycine, which is a quaternary alkaloid. The molecular formula is C5H12NO2, and the molecular weight is 117.5.
The molecular structure has two characteristics: first, the charge distribution in the molecule is neutral; Second, it has three active methyl groups. Its appearance is a flowing, slightly brown crystalline powder, sweet in taste, easy to absorb moisture, soluble in water and alcohol, neutral in water solution, melting point 293 ℃, able to withstand high temperatures below 200 ℃, and has strong antioxidant properties. In addition, betaine has moisturizing properties.

Betaine provides efficient active methyl for the body. After years of research, it was found that betaine, as an intermediate metabolite in animals, indirectly participates in animal protein and fat metabolism. From the perspective of its physiological mechanism, betaine is indirectly involved in many physiological metabolic processes in animals by providing methyl and synthesizing a variety of nutrients. Methyl is a necessary group for the synthesis of many substances with important physiological activities in animals, such as protein, carnitine, creatine, phospholipid, adrenaline, ribonucleic acid and deoxyribonucleic acid. Choline, one of the main methyl donors of animals, cannot provide methyl. It needs to be converted into betaine through mitochondria to have the ability to provide methyl, and to synthesize lipoproteins, amino acids and other substances. Therefore, When the supply of choline in the feed is insufficient, the addition of betaine can partially replace choline. The proper supplement of betaine in the diet can replace the methyl supply of methionine, another major methyl donor, so as to save methionine and improve the utilization rate of protein. The ability of betaine to provide methyl can also promote the synthesis of carnitine in animals and improve the intensity of fat metabolism.