Threonine Requirement of Female Broilers from 22 to 42 days of Age

Threonine is considered to be the third limiting amino acid for broilers. the aim of this study was to determine the threonine requirement of female broilers from 22 to 42 days of age. seventy five, one-day of age female broiler chicks (ross 308) were divided into five dietary treatment groups of similar mean weight, comprising 15 birds each, individually. they were fed a basal starter diet containing 23% cp, 3200 me kcal/kg, 0.91% threonine and 1.10% lysine (lys) during the first 3 weeks. at the end of the first feeding period, the broilers were randomly assigned to five dietary treatment groups receiving 0.70 (control diet), 0.75, 0.80, 0.85 and 0.90% of threonine. during the feeding period, growth performance parameters, body weight gain, feed intake and feed conversion ratio were determined.the results obtained in the experiment showed that the group receiving 0.75% threonine attained the best performance. the results of our investigation also showed that the highest body weight gain occurred at 0.75% threonine; the tendency in better feed conversion ratio in the group receiving 0.80% threonine for female broilers. our results suggest that the current nrc (1994), recommendation of 0.74% threonine for 21 to 42 days old broilers is adequate to support relative growth performance.