Improvement of innate immune responses and defense activity in tiger shrimp (Penaeus monodon Fab.) by intramuscular administration of the outer membrane protein Vibrio alginolyticus.

The Outer Membrane Protein (OMP) of Vibrio alginolyticus cell wall was administered intramuscularly (IM) to the tiger shrimp (Penaeus monodon Fab.) at 10, 20, 30 μg/kg bw. After 14 days infection, the tiger shrimps were challenged with 107 bacterial density of Vibrio harveyi for 24 hours. The total haemocyte count (THC), differential haemocyte count (DHC) and amount of total protein plasma (TPP), superoxide dismutase and protease enzyme activity were monitored. The results showed that intramuscular administration of OMP enhanced an immunomodulatory effect and protection against V. harveyi. The beneficial effect of OMP on the tiger shrimp is dose-dependent and OMP-20 μg/kg bw is an optimal dose after two times of boosters for 14 days against V. harveyi infection.