One thousand two hundred and fifty sexed day-old broiler chicks obtained from a commercial hatchery were divided randomly into five treatment groups (negative control, antibiotic and essential oil combination (EOC) at three levels) of 250 birds each. Each treatment group was further sub-divided into five replicates of 50 birds (25 male and 25 female) per replicate. The oil in the EOC was extracted from different herbs growing in Turkey. The EOC at 24, 48 or 72 mg/kg diet and an antibiotic at 10 mg avilamycin/kg diet were added to the basal diet. There were significant effects of dietary treatments on body weight, feed intake (except at day 42), feed conversion ratio and carcass yield at 21 and 42 days. Body weights were significantly different between the treatments. The birds fed the diet containing 48 mg essential oil/kg were the highest, followed by those receiving the diets containing 72 mg essential oil/kg, the antibiotic, the negative control and the 24 mg essential oil/kg at day 42, respectively. From 1 to 21 and 1 to 42 days of age, feed conversion ratios were improved significantly by the supplementation with 48 and 72 mg essential oil/kg diet. The feed intakes were significantly different between the treatments at 21 days, but not at 42 days. Supplementation in excess of 48 mg EOC/kg had no additional beneficial effect on body weight, feed intake, feed conversion ratio and carcass yield. The EOC, a feed additive of natural origin, may be considered as a potential growth promoter in broiler production.
Keywords: Essential oil combination, Herbs, Antibiotic, Performance, Broiler
South African Journal of Animal Science Vol.33(2) 2003: 89-94