Prof. Amel Mohammed Ahmed El Asely :: Publications:

The aim of the current study was to evaluate the role of Echinacea purpurea (E. purpurea) in protecting Oreochromis niloticus (O. niloticus) against Aeromonas hydrophila (A. hydrophila) infection. O. niloticus of an average weight 50 gm were fed diet containing 0 mg (control), 250 mg, 500 mg, 750 mg and 1000 mg E. purpurea powder/kg dry diet for 28 days (seven days before and 21 days after A. hydrophila infection). On the eighth day post feeding, all groups were intra-peritoneally infected with pathogenic A. hydrophila (108 CFU/ml). Initial count of A. hydrophila in the musculature immediately after infection was 11.91 log CFU/g. The immunological parameters, histopathological changes of liver and spleen and A. hydrophila count in the musculature of the infected fish were studied at the seventh, 14th and 21 days post infection in both control and E. purpurea fed groups. Dietary administration of E. purpurea to O. niloticus resulted in significant increase (p<0.05) in the circulating lymphocyte at 21 day post infection in the groups fed on 750 and 1000 mg E. purpurea incorporated diets, this increase was correlated with marked mononuclear cell infiltration around the blood vessels and well developed melano-macrophage center in the spleen. Moreover, serum electrophoresis showed marked increase in the band density in E. purpurea infected groups compared to control infected groups. The count of A. hydrophila in the musculature on day seven was significantly decreased (p<0.05) following feeding on 250, 500 and 750 mg E. purpurea incorporated diets as compared with the control, where it reached 5.41 log CFU/g (45.42%), 8.51 log CFU/g (71.45%) and 9.51 log CFU/g (79.85%) respectively. While, it reached 6.58 log CFU/g (55.25%) and 9.16 log CFU/g (76.91%) on day 14 following feeding on 250 and 500 mg E. purpurea incorporated diets, respectively. A. hydrophila count in the groups' fed 1000 and 750 mg E. purpurea incorporated diets reached to undetectable amounts at seventh and 14th day post infection, respectively. According to the present study, it could be conducted that E. purpurea was effective in protecting O. niloticus against A. hydrophila, and reducing the bacterial load in the musculature through enhancement of the fish immune system.