The effect of volatile oil mixtures on the performance and ilio-caecal microflora of broiler chickens

1. The aim of this study was to investigate the individual and combined effects of rosemary, oregano and fennel volatile oil (FVO) supplementation on the performance and ilio-caecal bacteriological flora of broiler chickens.A total of 800 male Ross-308 broiler chickens were divided equally into 8 groups; each contained 100 chickens. The study included a control treatment (NC) with no dietary additives that was supplemented with oils according to the following 7 treatments: 200mg -tocopherol acetate/kg (PC), 100mg oregano volatile oil (OVO)/kg, 100mg rosemary volatile oil (RVO)/kg, 100mg FVO/kg and an equal mixture of oregano+rosemary+fennel VO (100, 200, 400mg/kg, VOM-1, VOM-2 and VOM-3, respectively). The experiment lasted for 6weeks.At the end of the experiment, dietary supplementation with -tocopherol, oregano, rosemary and FVO and two different volatile oil mixtures (VOMs) (VOM-2; VOM-3) significantly increased the body weights (BWs) of broilers at 7, 14 and 21d of age compared to the negative control (NC) (-) and VOM-1 groups. At 0-42d, birds fed on VOM-3 were considerably heavier and also gained more weight than NC (-) and VOM-1 groups.The blend of VOs at 400mg/kg significantly increased Lactobacillus spp. in faeces. The blends of oregano, rosemary and FVOs (VOM-3) at 400mg/kg concentration and also VOM-3 group exhibited stronger antibacterial activity against coliform bacteria compared to the NC (-) group.In conclusion, the blend of oregano, rosemary and fennel VOs at higher concentrations (400mg/kg concentration) in diets can be used to stimulate the growth and can improve the intestinal microbial balance (including a reduction of coliform bacteria and an increase in Lactobacillus spp. counts) of broiler chickens.