Effect of dietary extract and dried areal parts of Rosmarinus officinalis on performance, immune responses and total serum antioxidant activity in broiler chicks

ObjectiveTo investigate effects of Rosmarinus officinalis compared with antibiotic and vitamin E on performance, immune responses and total serum antioxidant activity in broiler chicks.MethodsA total of 455 day-old broiler chicks (Ross 308) were assigned to one of 7 treatments, comprising 5 replicates in a completely randomized design including a basal diet (control) or either an antibiotic group; 4.5 mg/kg flavophospholipol, vitamin E; 150 IU/kg α-tocopherol acetate and also two different levels of rosemary containing 3 (RP1) and 7 g/kg (RP2) powder added to a basal diet. Furthermore, two different levels of rosemary either encompass of 2.5 (RE1) and 5.0 g/L (RE2) ethanolic extract were added to drinking water. Body weight, daily feed intake and feed conversion ratio were evaluated in different phases of the experiment. Antibody titers against sheep red blood cells, Newcastle and influenza disease viruses were measured on day 32 of age.ResultsBirds receiving RP1 possessed lower body weight than control group during starter and growing periods (P < 0.05). Supplementing RE1 decreased body weight on Days 28 and 42 of age compared with control group (P < 0.05). In comparison to control birds, carcass yield impaired in broilers given different levels of rosemary powder and rosemary ethanolic extract (P < 0.05). Although antibody titers were not affected by dietary treatments, supplementing RP2 and RE1 considerably improved total serum antioxidant activity compared with other dietary treatments (P < 0.05).ConclusionsIn conclusion, RP1 and RE1 deteriorated body weight of chickens in different periods. Inclusion of RP2 and RE1 resulted in improved total serum antioxidant activity.