Studying the Structure and Ultrastructure and Immunolocalization of the Gill Chloride cells in Caspian Kutum, Rutilus frisii kutum Fry

To investigate the branchial structure of the Caspian Kutum we used releasing fry’s (21-33 mg Body Weight). Study of the branchial tissue showed that in these fry’s branchial system was made up of 4 gill arch in each side of the head، one pseudobranch in each side of the head and one hemibranch at the posterior wall of the branchial chamber in each side of the head. Each gill arch bears gill filaments and lamella. Pseudobranch tissue is very similar to main gill tissue but it’s made up of lamellar shaped structures bound to each other. Immunolocalization of the chloride cells showed that these cells were located on the gill arch، gill filament، at the basis of the lamellae، pseudobranch and the hemibranch of the posterior wall of the gill chamber. Measurements of these cells showed that mean length was 9. 70±0. 28 µm and mean width was 6. 83±0. 24 µm. Ultrastructural studies showed that the most surface of the gill epithelia was composed of the pavement cells that have apical microridges and between them one can see the chloride cells with apical pit.