Immunomodulatory Activity of Solanum trilobatum Leaf Extracts in Oreochromis mossambicus

The application of plant-derived immunostimulants in aquaculture for the prevention of diseases is a promising new development. The objective is to study the effect of crude extract, water and hexane soluble fractions of Solanum trilobatum leaves administered intraperitoneally on the specific immune response, non specific immunity and disease resistance in Oreochromis mossambicus. The specific immune response was assessed in terms of primary and secondary antibody responses to Aeromonas hydrophila and serum lysozyme activity was measured to study the non-specific immune mechanism. The functional immunity in terms of percentage mortality and Relative Percent Survival (RPS) was assessed by challenging the fish with live A. hydrophila. All the doses of three fractions except 32 mg kg-1 of crude extract and 800 mg kg-1 of water soluble fraction significantly enhanced the primary and secondary antibody responses on most of the days tested. Almost all the doses of both water and hexane soluble fractions enhanced the serum lysozyme activity. In disease resistance test, the percentage mortality was significantly reduced in the treated groups which are reflected by RPS values ranging from 45 to 70. This preliminary study indicates the potential of using S. trilobatum for controlling infectious diseases in aquaculture. Divyagnaneswari, M., Christybapita, D. and Dinakaran, R.M. 2008. Immunomodulatory activity of Solanum trilobatum leaf extracts in Oreochromis niloticus, pp. 221-234. In Bondad-Reantaso, M.G., Mohan, C.V., Crumlish, M. and Subasinghe, R.P. (eds.). Diseases in Asian Aquaculture VI. Fish Health Section, Asian Fisheries Society, Manila, Philippines. Corresponding author: R. Dinakaran Michael, [email protected]