Betaine, also known as glycine trimethyl internal salt, is a non-toxic and harmless natural compound, quaternary amine alkaloid. It is white prismatic or leaf like crystal with molecular formula c5h12no2, molecular weight of 118 and melting point of 293 ℃. It tastes sweet and is a substance similar to vitamins. It has strong moisture retention and is easy to absorb moisture and deliquesce at room temperature. The hydrated type is soluble in water, methanol and ethanol, and slightly soluble in ether. Betaine has strong chemical structure, can withstand high temperature of 200 ℃ and has strong oxidation resistance. Studies have shown that betaine can partially replace methionine in animal metabolism.

Betaine can completely replace methionine in the supply of methyl. On the one hand, methionine is used as a substrate to form proteins, and on the other hand, it participates in methyl metabolism as a methyl donor. Betaine can promote the activity of betaine homocysteine methyltransferase in the liver and supply active methyl together, so that methionine demethylation product homocysteine can be methylated to form methionine from scratch, so as to continuously supply methyl for body metabolism with a limited amount of methionine as the carrier and betaine as the methyl source, Then, most of the methionine is used to form proteins, which can save methionine and use power. Together, betaine is further degraded after being methylated to produce serine and glycine, and then increase the concentration of amino acids in the blood (kamoun, 1986).

Betaine increased the contents of methionine, serine and glycine in serum. Puchala et al. Had similar experimental effects on sheep. Betaine can add amino acids such as arginine, methionine, leucine and glycine in serum and the total amount of amino acids in serum, and then affect the excretion of auxin; Betaine may promote the conversion of aspartic acid to n-methylaspartic acid (NMA) through vigorous methyl metabolism, and NMA can affect the composition and excretion of auxin in hypothalamus, and then the level of auxin in the body.