An essential amino acid, molecular weight (149.2) found in protein. Methionine is a sulphur-containing amino acid that is often deficient in diets for animals, particularly poultry. Among the cereal grains, only maize is considered a good source of sulphur amino acids (methionine + cysteine). Soybean meal is first limiting in sulphur amino acids for growth of poultry and swine.
Methionine reacts with ATP to form S-adenosylmethionine (SAM), the most impor-tant methylating compound in the body, facilitating the biosynthesis of up to 100 dif-ferent methyl-containing body compounds such as creatine, phosphatidyl choline and epinephrine. The polyamines, spermine and spermidine, also require SAM for their synthesis.
Methionine deficiency in poultry reduced growth, feed intake, body weight gain, egg size, production and increased feed conversion ratio for layers and breeders. Additionally, low methionine diets decrease laying performance and egg quality. Also, a deficiency of methionine results in poor feather growth and increased feather pecking. A methionine-deficient bird will tend to eat feathers in an attempt to obtain enough methionine. Feather pecking can quickly turn into cannibalistic behavior in a flock.
