An essential amino acid, molecular weight (119.1) found in protein. Because threonine contains a hydroxyl group on the β-carbon atom, it, along with serine, is often referred to as a hydroxy amino acid. Threonine is some-times a limiting amino acid in practical diets for growing animals. It is the second-limiting amino acid in soybean meal (after methionine) and in most cereal grains (after lysine). The endogenous proteins that enter the gut have a high concentration of threonine and may account for as much as one-half of the total dietary requirement for threonine.
In meat-type birds, depression of the growth rate, feed intake, and carcass yield are consequences of Threonine deficiency, whereas the effects in laying birds are a low laying rate, egg weight, egg mass, and feed conversion ratio.
