Studies on loose shell disease with special reference to enzyme chitinase Penaeus Monodon (FABRICIUS, 1798)

Loose shell infected Penaeus monodon was collected from Vellar estuary for a period of 2007- 2008. The collected samples were transferred to laboratory and analyzed. The results of present study revealed that, Vibrio count was varied from 9.3 to 21.5 x 105 CFU g-1 in gills, 11.2 to 35.6 x 105 CFU g-1 in gut and 9.2 to 31.2 x 105 CFU g-1 in hepatopancreas. Four types of Vibrio species were isolated from the loose-shell affected animals. Among them, Vibrio alginolyticus was dominant (31.94%) followed by V. anguillarum (25%), V. cholerae (19.44%), V. parahaemolyticus (13.88%) and unidentified Vibrio spp., (9.72%). The isolated Vibrio species were used for pathogenecity test on healthy P. monodon, V. parahaemolyticus caused the maximum mortality of 100% in 36 h at 0.05 ml dose. Histology revealed that marked changes in the tissues of gut, gill and abdomen of experimentally infected Vibrio inoculated shrimps. The protein was measured in quantitative, showed the more protein (0.95 mg ml- 1) concentration in infected than the normal animal and in qualitative detection of protein was done by SDS-PAGE clearly shows that there may be presence of enzyme chitinase in hepatopancreatic extract of infected shrimp. Key Words: Loose shell, Penaeus monodon, Vibrio, Histology