Comparative study of hemocytes of immune system and hepatopancreas of green tiger prawn, Penaeus semisulcatus in cold and warm seasons

Considering that green tiger prawn is important for fisheries and economic in the Persian Gulf region, understanding of the immune system and defense mechanism will lead to improved disease management in this species. In this study, hemocytes of the immune system and hepatopancreas in green tiger shrimp were compared in cold and warm seasons. For this purpose in total, 50 specimens of green tiger shrimp with a mean length of 19±1cm and a mean weight of 25±0.5g were prepared. Then 1mL of hemolymph combined with 1mL of anticoagulant and number and type of hemocytes were studied. Also for histological study, hepatopancreas was sampled from all shrimps and histological sections were prepared in usual methods. The results of this study indicated that in the cold season, the amount of all hemocytes increased. In both seasons, small granular hemocytes, without predominant change, were the highest in number and hyaline hemocytes were the lowest. In addition, a structural study of the hepatopancreas in both seasons showed that this organ was tubular, with the highest number of filamentary cells and the lowest amount of myoepithelial cells. There was a significant difference between absorptive-storage, bag and filamentary cells in both cold and warm seasons. Results of this study are consistent with the reports on other species and may be considered in vaccination cases due to stimulate and excite the immune system, especially during the cold season.