Pathology of aflatoxicosis and Heavy metal toxicity in pearl Spot Etroplus suratensis (Bloch) (Th 129)

Anikuttan, K K (2004) Pathology of aflatoxicosis and Heavy metal toxicity in pearl Spot Etroplus suratensis (Bloch) (Th 129). PhD thesis, Central Institute of Fisheries Education, Mumbai.

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Abstract

Food and water are the two major routes through which aquatic organisms are exposed to exogenous hazardous toxic insults. The pathology of the toxic impacts due to a food contaminant (aflatoxin B, or AFB,) and an environmental pollutant (cadmium) was studied in pearl spot, Etrop/us suratensis (Bloch). The influence of these two toxicants on various physiological indices as well as vital organs of the fish was studied in two separate experiments by exposing the fishes to either 400 ppb of AFB, or 9.4 ppm of cadmium for a period of 8 weeks. The physiological alterations due to aflatoxin exposure includes, an initial decrease followed by an increase in erythrocyte count; increase in leucocyte count, packed cell volume (PCV), serum alkaline phosphatase, aspartate aminotransaminase (AST) and alanine aminotransaminase (AL T); and a decrease in serum proteins. Histopathological and ultrastructural studies revealed progressive degenerative changes in the vital organs, liver, kidney, spleen and thymus. Liver sections revealed biliary proliferation and presence of pleomorphic, polyhedral and basophilic megalocytes invading into the normal parenchyma, which was diagnosed as hepatocellular carcinoma. The electronmicrographs revealed dilatation, fragmentation , proliferation and whirl formation of endoplasmic reticulum (ER), mitochondrial damages like condensation and loss of cristae and granules, nuclear changes like presence of perichromatin and chromatin granules, electron dense inclusions and presence of autophagosomes in the cytoplasm. The toxic insults due to cadmium were manifested as increase in ESR, AST and AL T and a decrease in PCV, serum proteins and alkaline phosphatase activity. Liver, kidney, spleen, thymus and gills exhibited severe degenerative changes at cellular and subcellular levels. Liver revealed coagulative necrosis and fibroblastic proliferation . The renal tubular epithelial cells were desquamated and periglomerular thickening as well as increased nuclearity were observed in glomeruli. The secondary lamellae of gills were elongated and fused together in cadmium exposed fishes. The major ultrastructural changes in the vital organs include ER fragmentation, mitochondrial swelling, presence of multivesicular bodies, autophagia, damage to desmosomes and cell membranes.

Item Type:Thesis (PhD)
Supervisor(s):George, K C
Uncontrolled Keywords:Pathology; aflatoxicosis; Heavy metal toxicity; pearl Spot; Etroplus suratensis
Subjects:Fish and Fisheries > Fish Toxicology
Theses
Fish and Fisheries > Fish Pathology
Divisions:CMFRI-Cochin > Fishery Environment
ID Code:7225
Deposited By:Dr. V Mohan
Deposited On:31 Jan 2011 16:32
Last Modified:20 Jan 2014 12:32

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