Effects of volatile oil additives on growth, carcass performances, and calcium and phosphorus concentrations in serum and bone of broilers

Abstract

Essential oils (herbal volatile oils) as alternatives to antibiotics are considered the most powerful natural feed additives. The aim of this study was to determine the effects of volatile oils and their mixtures (VOM) dietary supplementation on the performance, serum and tibia characteristics of broilers. A total of 800 male Ross 308 broiler chicks were equally divided into 8 groups of 100 chicks (10 replicates of 10 chicks each). The study included a control (NC) and diets supplemented with oils according to the following 7 treatments: 200 mg alpha-tocopherol acetate/kg (PC); 100 mg oregano oil /kg (OVO); 100 mg rosemary oil /kg (RVO); 100 mg fennel oil (FVO); oregano oil + rosemary oil + fennel oil - equally mixed - (100, 200, and 400 mg/kg, VOM-1, VOM-2 and VOM-3, respectively). The experiment was conducted for 42 d.At the end of the experiment, no significant differences were observed in feed intake and carcass yield. Dietary supplementation with mixed volatile oils (VOM-2 and VOM-3) and OVO improved the final body weight. Dietary treatments significantly influenced the feed conversion ratio (FCR) and bone ash (P< 0.001). Furthermore, the hot carcass weights of the OVO and RVO group and the volatile oil mixture group (VOM-2 and VOM-3) were significantly higher than for the NC group. FVO and VOM supplementation at both inclusion levels (VOM-2 and VOM-3) in the broiler diet significantly increased the bone Ca level compared with the other groups (p< 0.001). Moreover, the bone phosphorus percentage of the same groups (FVO, VOM-2 and VOM-3) were also significantly enhanced (p< 0.001) compared to the control groups (NC and PC). In conclusion, the results of this study showed encouraging improvement in performance and in tibia Ca levels in broilers when their diets were supplemented with VOM-3.