Mehdi Salmanzadeh, Yahya Ebrahimnezhad , Habib Aghdam Shahryar and Alireza Lotfi
The experiment was conducted to investigate the effects of in ovo injection of L-threonine on characters of hatching and growth performance broiler chickens. On the 8th day of incubation, 1008 fertile eggs, on based completely randomized design were divided into seven treatments with four replicates per treatment and 36 eggs per replicate. Experimental groups were following: 1) control (without injection), 2) injected with 0.5 ml deionized water (sham group), 3) injected with 15 mg L-threonine in 0.5 ml deionized water, 4) injected with 20 mg L-threonine in 0.5 ml deionized water, 5) injected with 25 mg L-threonine in 0.5 ml deionized water, 6) injected with 30 mg L-threonine in 0.5 ml deionized water and 7) injected with 35 mg L-threonine in 0.5 ml deionized water. At day 8 of incubation 0.5 ml on in ovo solution were injected into albumen. Upon hatch, chicks were weighed and transferred to experimental house and reared for 21 days. Results showed, in ovo injection had significantly lower percent hatching than control group. Also, Chicks weight from eggs injected with 30 and 35 mg L-threonine had significantly higher body weight as compared to sham and control group (P<0.01). The effect of injection of L-threonine wasn’t significantly on chick’s body weight grain on 21 days. The results of the study indicate that, effect of different levels of L-threonine injection had highest influence on improving the weight of newly-hatched chickens.
