THREONINE RESPONSES IN COMMERCIAL BROILERS AT 30 TO 42 DAYS

Threonine is typically: the third limiting amino acid in corn and soyb ean meal diets for broilers.,: However, reported threonine requirement values for broilers vary greatly, and the threonine: requirement for growing broilers has been studied little. It is important to accuratel y meet threonine requirements for maintenance and tissue accretion as the bird ages. Commercial broilers were fed threonine-deficient experi mental diets.::composed: of grain sorghum, peanut meal, corn, and poul try meal from 30 to 42 days of age, Performance of commercial broilers fed experimental diets containing surfeit threonine was equal to that of birds fed the corn and soybean meal control diet Results indicate that the 21::, 42 day NRC :threonine: requirement of 0.,74% of diet is too high, based on!the 30 to 42 day weight gain and feed:gain respons e. However,tbe 30 to 42 day threonine requirement for breast traits: m ay be higher than that of performance criteria. Future research should address threonine requirements in mature broilers for carcass traits.