Effects of Dietary Inclusion of the Encapsulated Thyme and Oregano Essential Oils Mixture and Probiotic on Growth Performance, Immune Response and Intestinal Morphology of Broiler Chickens

This study was conducted to investigate the effects of dietary inclusion of the encapsulated thyme essential oil (TEO), oregano essential oil (OEO) mixture and probiotic on growth performance, immune response and intestinal morphology of broiler chickens. A total of 490 one-day-old Ross 308 broiler chicks were randomly divided into seven treatments consisting of five replicates (n=14). Birds were fed with 1) basal diet (control), and a basal diet containing; 2) 10 mg Avilamicine antibiotic, 3) 200 mg/kg encapsulated TEO+OEO mixture, 4) 200 mg/kg non-capsulated TEO+OEO mixture, 5) Pronigeb (R) (probiotic), 6) Pronigeb (R) with 200 mg/kg non-capsulated TEO+OEO mixture and 7) Pronigeb (R) with 200 mg/kg encapsulated TEO+OEO mixture. Results revealed that birds fed diet containing antibiotic, encapsulated TEO+OEO mixture with and without probiotic had significantly higher body weight gain (BWG) compared with control and non-capsulated TEO+OEO mixture groups on day 42 (P < 0.05). Dietary inclusion of TEO+OEO in capsulated form and also in along to probiotic increased humoral immunity in broiler chickens compared with other groups (P < 0.05). Birds fed the diet supplemented with different types of additives showed significantly higher dinitrochlorobenzene (DNCB) compared with the control group at 32 days of age (P < 0.05). Dietary inclusion of the encapsulated EOs with and without probiotic both significantly increased villus length and villus width in comparison to other groups (P < 0.05). The highest and lowest ratios were observed for the control group and probiotic+encapsulated TEO+OEO group respectively. These results indicate that feeding birds with diet containing encapsulated EOs alone or together with probiotic could improve BWG, immune responses and intestinal morphology in broiler chickens.