Histomorphological characterization of immune system in greasy grouper, Epinephelus tauvina (Forsskal, 1775)

Patra, Sushanta Kumar (2006) Histomorphological characterization of immune system in greasy grouper, Epinephelus tauvina (Forsskal, 1775). PhD thesis, Central Institute of Fisheries Education, Mumbai.

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Abstract

The greasy grouper, Epinephe/us tauvina is one of the major candidate species cultured in saltwater ponds and cages all over the world. There is scanty information on immunology of the species and thus an attempt was made to characterize the immune system of the species. The peripheral leucocytes of the species were characterized by means of routine haematological techniques, cytochemical methods and transmission electron microscopy. The haemopoietic organs like thymus, kidney and spleen of the species were studied by routine histology and electron microscopy. The mean total erythrocyte and leucocyte counts were 4.42 x 10 6/mm3 ± 0.69 and 72.75 x 10 3/mm3 ± 0.85 respectively. The mean serum total protein, albumin, globulin and albumin/globulin ratio were 2.04 g % ± 0.23, 0.05 g%± 0.01 , 1.95 g %± 0.21 and 0.02 ± O. 002 respectively. The electrophoretic separation of sera of the greasy grouper yielded 8 to 10 bands of which 4 to 5 bands were prominent. The differential counts of the blood contained three types of leucocytes namely granulocytes, lymphocytes and monocytes. The granulocytes were positive for peroxidase, sudan black B, PAS and mildly positive for acid phosphatase. The ultrastructure of granulocytes indicated two types of cells and the majority of them had homogeneous electron dense cytoplasmic granules while the other had crystalloid granules. The mean lymphocyte count was 61 .83 % ± 2.67 and two types of lymphocytes, large and small lymphocytes, were noticed. The fine structures of the lymphocytes consisted of nucleus with euchromatin and heterochromatin and the cytoplasm contained mitochondria, numerous polyribosomes and stacks of rough endoplasmic reticulum. The monocytes formed 6.33 %± 1.30 of total leucocytes which were positive for PAS and acid phosphatase. The monocytes had foamy cytoplasm with peripherally located nucleus. The cytoplasm of monocytes contained Iysosomes, mitochondria and rough endoplasmic reticulum. The thymus was surrounded by collagenous capsule and divided into several lobules by trabeculae. The lobules were supported by the reticular connective tissue, in which epithelial cells and Iymphoblasts were seen. The ultrastructure of the thymus revealed capillaries lined by endothelial cells having tight junction and the lumen of the capillaries were filled with blood cells. The spleen was surrounded by the capsule and a random distribution of the mesenchymal and parenchymal tissue were noticed. The capillaries were enclosed with reticular-collagen fibre sheath and filled with macrophages and Iymphoblasts. The ultrastructural studies revealed the phenomenon of haemopoieosis in spleen. The kidneys showed the presence of haemopoietic tissue in both histological and ultrastructural studies. Inflammatory studies yielded biphasic exudation of neutrophils and Iymphoblasts at the site of injection. In vivo phagocytosis studies on Indian ink revealed carbon filled phagocytes in the peritoneum at 24 h post injection and the phagocytic index was 30.15% ± 0.46. The skin sensitivity test using PHA showed thickening reaction which prolonged more than 72 h. The rosette forming cells with rabbit erythrocytes were 39.67 % ± 0.71 .

Item Type:Thesis (PhD)
Supervisor(s):George, K C
Uncontrolled Keywords:Histomorphological characterization; immune system; greasy grouper; Epinephelus tauvina; Forsskal
Subjects:Fish Biotechnology
Theses
Demersal Fishes > Groupers
Divisions:CMFRI-Cochin > Marine Biotechnology
ID Code:7665
Deposited By:Dr. V Mohan
Deposited On:19 Feb 2011 15:02
Last Modified:20 Jan 2014 15:47

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