Efficiency of Levamisole in Improving the Immune Response of Catfish (Clarias Gariepenus) to Aeromonas Hydrophila Vaccine: Clinico-Pathological Studies

Abstract

The effect of Levamisole on the immune response of 200 catfish (Clarias gariepenus) was evaluated. Fish were divided into 4 equal groups, reared in a glass aquaria and fed on a basal diet. The 1 st group served as a control. Fish of the 2 nd group was incorporating Levamisole (150mg/kg diet fed-1) for 2 months. The 3 rd and 4 th groups was vaccinated using Aeromonas hydrophila bacterin, at the first day of experiment, but fish of 4 th group was fed on diet containing same dose of levamisole throughout the 2 months of experiment. At 1 st , 3rd and 5 th week, blood samples were collected from all groups for hematological, immunological and serum biochemistry studies while fish of 2 nd group were subjected to histopathology. Challenge was done to all groups, at thirty day of experiment, through immersion of fish in virulent Aeromonas hydrophila (1g bacterial cells/liter) for 10min, the mortalities recorded and the dead fish used for the bacterial re-isolation. Catfish of 1 st group showed normal values throughout the period of the experiment. Fish of 2 nd group showed activation of melanomacrophages. Hyperplasia of hematopoietic tissue was evident at 3 rd -4 th week. Degenerative changes were mild at 1 st -2 nd week and become prominent at 5 th week. Fish of 3 rd group showed a significant gradual increase of leucocytes, phgocytosis, antibody titer, total protein and globulin, at 1 st -5 th week post-vaccination. Fish of 4 th group showed higher hematological and immunological values than those of 3 rd group. The relative level of protection after the challenge infection was 30, 85 and 90% for the 2 nd , 3 rd and 4 th groups; respectively. The histopathological finding of this experiment showed the safety of the selected dose of levamesol on catfish. The other findings indicate its efficiency as immunostimulant in improving the immune response of catfish to Aeromonas hydrophila vaccine.

Histopathology of head kidney tissues in challenged rohu, Labeo rohita Hamilton after vaccinating with Aeromonas hydrophila antigens

“…Aly et al. [36] observed histopathological finding in kidney such as vacuolar degeneration of catfish ( Clarias gariepenus ) treated by levamisole-adjuvanted A. hydrophila vaccine. Our results also corroborate the finding of Julinta et al.…”