Effect of dietary amino acid density and strains on performance and carcass characteristics of Arian broilers

An experiment was conducted to investigate the effect of different levels of dietary amino acid on performance and carcass characteristics of two types of Arian strains (Classic and New). Nine hundred and sixty day old chicks were used. Experimental group consisted of two broiler strains and three levels of digestible amino acid. Digestible lysine levels were used as an indicator and the other amino acids were balanced according to lysine concentration. Each experimental group had four replications with40 chicks (20 male and 20). Feed and water were freely available to the chicks. During the experiment periods، feed intake and body weight were measured weekly. At the end of the experiment، 8 birds (4 female and 4 male) from each replicate were slaughtered and carcasses percentage، breast، drumsticks and abdominal fat were determined. Data were analyzed according to 3×2 factorial methods with completely randomized designs. The difference between body weights of Arian strains was significant only for 7 days of age (p<0. 05). Feed intake was not affected by the type of strains at 28 days of old but after this age the difference between strain was significant (p<0. 05). Feed conversion ratios for the periods of 0-14 and 0-21 were affected by strains (p<0. 05). Body weights، cumulative feed intake and feed conversion ratio at 42 days of age were not affected by the different levels of dietary amino acid concentrations. However، the level of amino acids had significant effect on feed conversion ratio in 0-7، 0-14 and 0-21 periods.