Immunostimulating and Growth Promoting Activity of Dietary Levamisole on Cirrhinus mrigala Fingerlings

The effects of supplementing diets with levamisole on growth, immune response and resistance against pathogenic Aeromonas hydrophila were determined. Fish were assigned to three treatments with different level of levamisole (125, 250 and 500 mg kg ̄1 diet) and the control diet was prepared without levamisole. Cirrhinus mrigala were fed at 4% of their body mass for 60 days. Growth performance, enzyme activities and immunological parameters were analyzed among groups. The total erythrocyte count, total leucocyte count, phagocytic activity and NBT reduction were significantly (P<0.05) enhanced in levamisole treated group when compared to control. The relative percentage survival, A. hydrophila post-challenge was significantly higher in fishes fed on 250 mg kg ̄1 of levamisole supplemented diet. The same dose also resulted in significantly high specific growth rate (SGR), feed conversion ratio (FCR), apparent protein digestibility (APD) and elevated intestinal enzyme activities compared to other groups. Thus, administration of 250 mg of levamisole kg ̄1 diet is recommended for enhancement of immunity, growth and survival of C. mrigala hence acting as a potent immunostimulant agent