The effects of Echinacea purpurea L. (purple coneflower) as an antibiotic growth promoter substitution on performance, carcass characteristics and humoral immune response in broiler chickens

This experiment was conducted to examine the effects of using different forms and levels ofEchinacea purpurea L. (EP) in comparison with an antibiotic growth promoter (flavophospholipol) on performance, carcass characteristics and immune responses of broiler chicks. In this trial, 336 one-day-old broiler chicks (Ross 308) were weighted and randomly assigned to the 7 treatment groups, each with 4 replicates and with 12 broilers in each replicate. The 7 treatments were as follows: Basal diet (control), Basal diet + antibiotic (4.5 mg flavophospholipol/kg diet), Basal diet + dried aerial part powder of EP continuously (5 g/kg diet), Basal diet + the dried aerial part powder of EP continuously (10 g/kg diet), Basal diet + the ethanolic extract continuously (0.25 gr/kg diet), Basal diet + the dried aerial part powder of EP with 3-days application followed by 11 application free days intermittently (5 g/kg diet), and Basal diet + the dried aerial part powder of EP with 3-days application followed by 11 application free days intermittently (10 g/kg diet). The contents of flavonol-o-glycosides as quescetin in the Echinacea dried aerial part and the ethanolic extract were determined, and the amount of flavonol-o- glycosides as quescetin in the 5 g/kg diet EP continuously to the ethanolic extract was equal. At the 28th and 31st day, blood samples were taken and analyzed for immune responses. The results showed that the use of the 5 g/kg diet EP continuously led to the highest DFI, DWG and antibody titres against sheep red blood cell (SRBC) and Newcastle virus when compared to other groups. The intermittent application of 10 g/kg diet EP had significant effect in the grower period on DWG, FCR and immune responses against SRBC (p<0.05). DFI and DWG were increased by 5 g/kg diet EP continuously than the ethanolic extract significantly (p<0.05). The percentage weight of carcass traits were not affected by dietary treatments except for the percentage of the small intestine that decreased in the intermittent groups (p<0.05). In conclusion, performance and immune responses of broiler chicks were improved by continuous application of 5 g/kg diet EP.   Key words: Broilers, Echinacea purpurea L., performance, immune responses, carcass characteristics.