Study of performance and carcass characteristic of broiler chickens fed diets based on wheat and barley contain different levels of vitamin premix in battery bage system

This experiment was conducted to evaluate the performance and carcass characteristics of broiler chickens which were fed with wheat and barley based diets with different levels of vitamin premix in battery cage system from 29-42 days. A total of 112 male broilers (Ross 308) were allocated to 7 treatment groups, with 4 replicates per treatment group and 4 birds per replicate pen. The treatments were composed of 0, 33.33, 66.66 and 100 percent of vitamin premix (according to the recommendation of vitamin premix Producer Company) which used from 29 to 42 days; moreover, three treatments were composed of 0, 33.33, 66.66 and 100 percent of vitamin premix, which were eliminate from the diets at age 36-42 day. At the 35 and 42 days of age live weight and feed intake of each replicate were measured and the average of feed intake, body weight gain and feed conversion ratio were calculated. In two periods of 35 and 42 days after the slaughter, carcass yield, percentage of thigh and breast meat, abdominal fat and liver were measured. The results showed that birds fed with different levels of vitamins had no significant differences (P>0.05) on productive performance and carcass characteristic in the period of 29-35 days of age in finisher period, but birds which were fed on diets without vitamin premix (zero level) in the period of 36-42 days of age had significant difference with other levels (P>0.05). Therefore, it seems according to the lower level of vitamin premix (33.33%) there is the possibility of reduction of its level during finisher rearing of broiler chickens in battery cage system.