This research was carried out to determine the effects of cinnamon oil (Cinnamomum zeylanicum L.) added to diet at various concentrations on growth performance and carcass characteristics in heat stressed quail (Coturnix coturnix Japonica). The quails (n=180, 15 days age), which were exposed to two different temperatures (Thermo-neutral and heat stress) and three different concentrations of cinnamon oil (0, 250 and 500 mg/kg), were divided into 6 groups according to 2x3 factorial design. All groups were balanced according to initial live weight and gender.

Effect of the heat-stress was found to be significant on live weight (P<001), live weight gain (P<0.05) and feed consumption (P<0.05), while effect of cinnamon oil was not found significant (P>0.05). Both heat–stress and the cinnamon oil on feed conversion ratio were not found significant (P>0.05). Heat stress affected significantly on other carcass parameters [hot carcass ratio (P<0.05), cold carcass ratio (P<0.05), spleen ratio (P<0.001) and heart ratio (P<0.01)] except liver ratio (P>0.05).

As a result, the effect of cinnamon oil which is added to basal diet on the performance and carcass traits statistically was found to be not significant.