S Kakoolaki - Department of Aquatic Animal Health, Iranian Fisheries Research Institute, Tehran, Iran
L Sharifpour - Department of Aquatic Animal Health, Iranian Fisheries Research Institute, Tehran, Iran
M Soltani - Department of Aquatic Animal Health, Faculty of Veterinary Medicine, Tehran University, Tehran, Iran
H.A Ebrahimzadeh Mousavi - Department of Aquatic Animal Health, Faculty of Veterinary Medicine, Tehran University, Tehran, Iran

Objective: During 2002, a rapid and high mortality occurred in cultured P. indicus farms in Iran. The mortality reached up to 90% within 3-10 days. Therefore, disease prevention became a priority and shrimp immunology has become a prime area of research. The aim of the present study was to describe hematocytes in Fenneropenaeus indicus. Method & Materials: Hemolymph was collected from 10 adult shrimps, Fenneropenaeus indicus (weight ranging from 9 to 11 g) obtained from a semi-intensive farm in Bushehr Province, in south of Iran. Shrimps were acclimatized in a tank containing clean and aerated seawater with 34 ppt salinity at 24-26oC in Persian Gulf Higher Education Center for Fisheries Science for 2 days before collecting the hemolymph. Results & Conclusion: Hemocytes were classified to three types as agranular (hyaline), small-granule and large-granule cells. Hyaline cell (HC) represented approximately 10-15% of the circulating hemocytes in F. indicus. It was round, ovoid, or fusiform hemocyte (7.07 length×5.14 width in μm) having a relatively large nucleus (5.84 length × 4.32 width in μm). Small granule cell (SGC) comprised approximately 60_65% of the total circulating hemocytes in F. indicus. These ovoid or fusiform cells (11.24×4.92 μm) had a low nucleucytoplasmic ratio (with average size of nuclei, 6.29×4.26 μm) compared to that of the HC. Large granule cell (LGC) represented about 20-25% of the total circulating hemocytes in F. indicus. These cells were round or ovoid and stable cells (10.97×7.84 μm) which have low nucleucytoplasmic ratio (with average size of nuclei, 6.8×6.26 μm) compare to that of the HC. Granulocytes are involved in the immune system the same as hyaline cells. However, as it has been previously proved, it seems that hyaline cells start some reaction such as clot formation.

Hemocytes, Feature, Phagocytosis, Fenneropenaeus indicus