Effects of Echinacea purpurea on resistance against infection with Aeromonas hydrophila in grass carp (Ctenopharhyngodon idella)

Objective: Echinacea purpurea has a long history of medical use for a variety of conditions, particularly infections, and today Echinacea products are among the best-selling herbal preparations in several developed countries. Modern interest in Echinacea is focused on its immunomodulatory effects, particularly in the prevention and treatment of viral and bacterial infections. However, there are few documents about immunostimulatory effect of Aloe vera in fish. In this study, the effect of administration (oral & interaperitoneal route) of Aloe vera on resistance of grass carp to Aeromonas hydrophila has been evaluated. Method & Materials: 200 healthy grass carp (average weight= 20±3.43g) were divided into 4 groups. Group 1 received 400 mg/kg Echinacea in intra-peritoneal route (i.p.). Group 2 received 0.5% Echinacea powder in their daily food (oral). Group 3 received normal saline i.p. route as a control group for i.p. Group 4 did not receive any treatment (control oral). After 20 days in groups 1 & 3 and after 40 days in groups 2 & 4 the fish were challenged with 2×LD50 Aeromonas hydrophila in i.p route. Mortality in each treatment was recorded daily for 14 days and cumulative mortality curve were drawn. Results & Conclusion: Mortality in i.p. and oral treatments started from days 6 & 3, respectively, versus it started from day 2 in both controls groups. Cumulative mortality curve showed that after 14 days 100% mortality occurred in both control groups but 75% and 40% mortality observed in oral and i.p treatments, respectively. Rate of mortality varied significantly in different groups (P<0.005). i.p and oral treatment showed lower mortality rate but i.p treatment showed significant difference from the others (P<0.005). Results showed no significant difference between two control groups (P>0.005). Conclusion: Administration of Echinacea purpurea in grass carp in i.p and oral routes increases resistance to Aeromonas hydrophila infection. i.p rout is more efficient than oral route. Grass carp immune system (specially non-specific arm) should be influenced by Echinacea and consequently resistance to Aeromonas hydrophila increased. According to the results of this study Echinacea can be used as an immunostimulator in grass carp to increase resistance to bacterial infections, the same as their use in other mammalians particularly human.

کلیدواژه ها:

Echinacea purpurea ، Ctenopharhyngodon idella ، Aeromonas hydrophila ، resistance