Journal of Pharmaceutical Research International

Aims: The present study evaluated the efficacy of dietary doses of Lactuca indica extract on immunological parameters and disease resistance against Aeromonas hydrophila infection in mono-sex Nile tilapia, Oreochromis niloticus.
Place and Duration: This experiment was performed in the Laboratory of Fisheries and Marine Bioscience (FMB), Jessore University of Science and Technology (JUST), on July to December 2013.
Methodology: Lactuca indica extract preparations, harbal diet preparations, Aeromonas hydrophila Isolation, specific and non-specific immunological assays (following phagocytic activity and serum agglutination) and challenge test were performed.
Result: A. hydrophila is a more drastic disease producing and common cause of bacterial haemorrhagic septicaemia, it is a gram-negative, non spore-forming, rod-shaped, yellowish colony forming bacteria. Fishes were fed with L. indica extract at 0%, 0.5%, 1%, 1.5% and 2.0%; among those 2.0% showed highest significant responses in phagocytic activity, specific growth rate, specific and non-specific immune responses on week 2 and 4 compared to control diet whereas the changes did not manifest on first week. All groups fishes were injected intraperiotonaly (i.p.) with A. hydrophila at 3.5×10-7 CFU ml-1 for analyzing cumulative mortality on 30th day of feeding. L. indica enriched diet at 2.0% level resulted in lowest mortality (20%) indicating highest protection (Relative Percent Survival, RPS 75%) from A. hydrophila infection than 0.5%, 1.0% and 1.5% doses diet that resulted 72%, 56% and 32% mortalities respectively. 2% dose also showed highest growth compare to other doses.
Conclusion: The results suggest that the dietary supplementation of L. indica extract stimulates immunostimulants, reduce mortality and increases disease resistance in O. niloticus against A. hydrophila infection.