Abstract

Two trials were conducted to examine the effect of Satureja khuzistanica essential oils (SkEO) on productive performance using 420 Cobb 500 broiler chicks. SkEO was added into drinking water at high doses (0.5 to 2.5 g/L) up to day 28 (Trial 1) and then it was reduced to 0.5 < g/L up to day 42 of age (Trial 2). The SkEO-treated water significantly decreased weight gain, feed intake, water intake and feed-to-gain, and carcass weight in a dose-dependent linear trend up to day 28 of age (Trial 1; P < 0.05). The mean abdominal fat percent significantly decreased in the treated birds and it was lower for the male birds which received 0.5 g/L SkEO compared to the other birds of the same sex. The birds regained somewhat in all zootechnical indices by lowering the SkEO doses (0.2, 0.3 and 0.5 g/L) in Trial 2. In conclusion, SkEO at high doses (0.5 to 2.5 g/L) adversely affected production performance of broiler chicks up to day 28 of age. The adverse effect was found to be fairly reversible by lowering the SkEO doses in advanced ages.

Key words: Broiler chicken, carcass defects, productive performance, Satureja khuzistanica.