The Effect of Different Levels of Threonine on Performance and Carcass Characteristics of Broiler Chickens

This study was conducted to investigate the effect of different levels of threonine on performance and carcass characteristics of broilers on 160 mail Ross 308 broiler chicks in a completely randomized design with 4 treatments and 4 replicates for each treatment for forty-two days. Basal diet containing corn, soybeans and wheat was regulated recommendations based catalogs of Ross.Incremental levels of threonine supplementation were added to the basal diet to 4 treatments in a range of 94(control),105,110 and 115 percentage of threonine be provided.Traits major were feed intake ,weight gain, feed conversion ratio, Carcass Characteristics and total cost of nutrition were measured at the end of 42 days.The results of this study indicated that in total period of the breeding,the highest feed intake and weight gain is related to treatments of threonine 110 and 115 percentage,therefore the best feed conversion ratio has been achieved with the use of these treatments.The results of Carcass characteristics indicated that threonine 115 percentage treatment has the highest percentege of carcass and control is minimal.Also,the highest percentaje of abdominal fat related to 115 percentage treatment and the lowest it percentage is related to threonine 105 percentage treatment.The highest relative percentages of heart,bursa fabricius and breast was obtained with threonine 115 percentage treatment ,however , the relative percentages of liver,thigh and gizzard was not affected by different levels of dietary threonine .Finally the lowest feed cost per kg of body weight was observed with threonine 115 percentage treatment.