Effects of Echinacea purpurea extract on the immunological response to infectious bursal disease vaccine in broilers

Abstract

Echinacea purpurea is among the most widely used herbal medicines throughout Europe and North America for the prevention or treatment of infectious diseases. However, there have been few reports on the effect of the herb in chickens. In order to investigate the immunomodulatory effect of Echinacea purpurea in fowls, 150 seven-day-old broilers were randomly divided into five groups (30 in each group). Birds in Groups A, B, and C were orally given Echinacea purpurea extract once a day at low (0.1g, Group A), medium (0.5g, Group B), and high (1g, Group C) doses for seven days, while Group D and Group E, assigned as control Group I and control Group II, respectively, were given distilled water in the same amount as Groups A, B, and C. Broilers in Groups A, B, C, and D were normally immunized with infectious bursal disease (IBD) vaccine at 14-day-old, whereas Group E was neither treated with Echinacea purpurea extract nor vaccinated. Results indicated that antibody titers were higher (P<0.01) in the three Echinacea purpurea extract treated groups (Groups A, B, and C) compared with Group D on days 21, 28, 35, and 42 after treatment. The antibody titer raised more strikingly in groups treated with higher doses of Echinacea purpurea extract (0.5g and 1g) than lower dose (0.1g). The IL-2 level in peripheral blood was significantly higher in Groups B and C compared with Group D (P<0.01 on day 21 and P<0.05 on days 28 and 35). No significant difference was observed between Group A and Group D. The TNF-α content in Group B was significantly higher than that of Group D (P<0.01 on day 21 and day 28, P<0.05 on day 35). Birds in Group C also showed a higher TNF-α content than Group D (P<0.05 at the three measuring dates). These results indicated that Echinacea purpurea extract significantly enhanced IL-2 and TNF-α production and antibody titers to the IBD vaccine. The Echinacea purpurea extract was also found to increase the feed conversion ratio.

Keywords

Echinacea purpurea extract / antibody / IL-2 / TNF-α / infectious bursal disease / broiler