A total number of 378 unsexed 7 d old cobb boiler chicks were randomly divided among nine dietary treatments, with six replicates per treatment, seven birds each, to investigate the effect of sweet basil (Ocimiumbasilicum L.), thyme (Thymus vulgaris L.) and their oils as natural fee7723*23d additives on broiler performance, blood parameters, immune response, and total bacterial count. Experimental chicks were fed the same basal diet and submitted to the following dietary treatments: the first group fed a commercial broiler basal diet without supplementation (control), while the 2nd and 3rd groups fed basal diet supplemented with 10 and 20 g/kg of sweet basil powder, the 4th and 5th groups fed basal diet supplemented with 0.5 and 1g/kg of sweet basil oil, the 6th and 7th groups fed basal diet supplemented with 5 and 10 g/kg of thyme powder and the 8th and 9th groups fed basal diet supplemented with 0.5 and 1g/kg of thyme oil. Growth performance, production index and economical efficiency were calculated. At the end of the experiment (39 d old), some carcass characteristics, blood constituents and bacterial count of the digestive system were measured. Results showed that broiler fed basal diet supplemented with sweet basil, thyme and their oils had significantly greater BW, BWG, economical efficiency, production index compared to control. All supplementations decreased serum AST, ALT, total lipids, triglycerides, cholesterol, LDL and increased T3, TAC, GSH, GPX, SOD, glucose, total protein, γ-globulin, globulin, IgM, IgG, LA, BA, LTT, phagocytic activity, phagocytic index, RBCS and Hb compared to control. All supplementations increased percentage of dressing and total edible parts compared with control. However, all supplementations decreased total bacterial count, Salmonella and E.Coli compared to control.
In conclusion, either sweet basil or thyme and their oils could be used safely as a natural growth promoters to improve growth and immune response of broiler chick.