Betaine, also known as trimethylglycine, is a non-toxic and harmless natural compound widely existing in animals and plants. Its molecular formula is C5H12NO2, molecular weight is 117.15, and its chemical structure is similar to choline and methionine. Betaine has stable physical and chemical properties, which will not denaturate at 200 ℃. At room temperature, betaine is white and crystalline, which is easy to deliquate. Betaine has many important functions in the health and performance of broiler chickens, especially under conditions of heat stress. The addition of betaine to poultry feed can enhance immunity and provide active methyl.

Betaine is a trimethyl derivative found in living organisms in deserts and low rainfall areas. It acts as an osmolyte to help maintain cellular water balance and as a methyl donor through methionine recycling. Increased water retention due to the osmolytic effect of betaine increases the volume of the cell, thereby increase the anabolic activity, integrity of cell membrane and overall performance of the bird.

Methyl is an indispensable component of poultry metabolism. The synthesis of proteins, lipids, carnitines and other substances is inseparable from methyl. However, animals cannot synthesize methyl by themselves, so they must be ingested. At present, methionine, choline and betaine are the main sources of methyl needed by poultry. Methionine can provide methyl for the body after conversion to S-adenosyl methionine, but methionine is expensive and will increase the cost of breeding. Choline cannot provide methyl directly, but can provide active methyl only after choline oxidase is catalyzed by a series of reactions. This process is complex and energy consuming, and is easily interfered by various factors between cell membrane and mitochondria, which is not conducive to methyl utilization. Betaine has three active methyl groups, which can be directly used by the body and is not affected by the above factors.