Effect of drinking thyme essence on performance, energy and protein efficiency and economical indices of broiler chickens

Five hundred one-day old male chicks (Ross-308) were assigned based on a completely randomized design (CRD) and divided into 4 treatments with 5 replicates. Treatments were arranged in: Control group (plain water)، 0. 1 ml/lit (0. 1%)، 0. 15 ml/lit (0. 15%)، and 0. 2 ml/lit (0. 2%) of thyme essence added to drinking water. Rations for all of the treatments were the same with respect of energy، protein minerals and other nutrients regarding to 3 growth phases including: 0-7، 8-21 and 22-42 days of rearing period. After day 7 chicks weighed and assigned to treatments randomly. Performance traits including: growth rate (average daily gain، feed intake and FCR) also economic efficacy and efficiency of energy and protein intake were calculated. Economic indices including point spread، performance index and production index were calculated base on the final data at the end of experiment. According to results feed intake، gain and FCR were different between groups significantly (p<0. 05)، so the thyme essence treatments had improved means comparing to control group. The most feed intake and average daily gain pertained to level of 0. 2% thyme essence and the lowest to the control group. The highest gain per protein intake (kg/kg) and the lowest energy intake per average daily gain (cal ME/g) pertained to level of 0. 2% thyme essence (p<0. 05). Ratio of energy/protein was not significant between the treatments. Also the greatest economic indices including point spread، performance index and production index pertained to levels of 0. 2 and 0. 15 % thyme essence (p<0. 05). As a final finding we can claims that using of drinking thyme essence at levels of 0. 2 and 0. 15 % could improve performance traits، energy and protein efficiency and economic indices in broiler chickens.