Effect of immunostimulants on the haemolymph haemagglutinins of tiger shrimp Penaeus monodon

The levels of haemagglutinins in Penaeus monodon, following administration of immunostimulants, beta-glucans and/or vibrio bacterin either orally or by immersion, were studied. The freshly drawn haemolymph was incubated with microbial materials like beta-glucans/vibrio bacterin and serum obtained after coagulation was administered to naive animals. The immunostimulant treatments either via immersion, feeding or injection were found to cause an increase (P < 0.000) in haemagglutination activity (HA) of the haemolymph against mouse erythrocytes. Injection of saline or heterologous haemotymph caused an increase in the HA, but injection of haemolymph serum obtained by clotting haemolymph in the presence of vibrio bacterin or glucan did not bring about an increase in HA. There was no change in the haemolymph protein profile of the groups receiving immunostimulants through immersion or feed. Two protein bands (27 and 30 kDa), which were present in the uninjected group, were found to be over-expressed in the haernolymph-injected groups. Three bands of 1-7,21 and 23 kDa, which were absent in control or saline-injected groups, were present in all the haemolymph serum-injected groups. The study indicates that modulation of HA may partly account for the immunomodulatory activity of immunostimulants like beta-glucan or vibrio bacterins.