STRESS RELATED HISTOPATHOLOGICAL CHANGES IN THE HEPATOPANCREAS OF BOTH THE SEXES OF PALAEMONID PRAWN MACROBRACHIUM DAYANUM (HENDERSON) (CRUSTACEA : DECAPODA)

Abstract

The palaemonid prawns Macrobrachium dayanum(Crustacea: Decapoda) are important species found in river Gomti and are very good bioindicators. These prawns are ideal animals to study the histopathological impairments caused by the effect of heavy metals prominent in river Gomti. The test animals were exposed to LC50value (0.15 mg/l and 0.16 mg/l respectively)at acute exposure for 24, 48,72 and 96h and at subacute exposure25% of 96hr LC50 values of CdCl2 for males and females (0.0375mg/l & 0.04 mg/l) respectively for 10, 20 and 30 day exposure. The histopathological changes were studied in both the sexes in the animals.Marked histopathological
changes were noticed in hepatopancreas of M.dayanum after cadmium chloride exposure. At 96 h acute exposure, hepatopancreas showed vacuolization in epithelial cells, necrosis in tunica propria, increased number of migratory cells, granuloma in intertubular connective tissue alongwith karyorrhexis and karyolysis in cells. Necrotic and degenerative changes in hepatopancreatic epithelium, which were mainly, noticed in R and B cells. Loss of histological architecture along with the heavy influx of haemocytes was recorded at this stage. After sub-acute exposure large vacuoles, particularly R and B cells were observed along with hypertrophy, necrosis and degenerative changes at most of the places in hepatopancreatic epithelium. Karyorrhexis and pyknosis were common. Increased number of migratory cells in intertubular spaces was a peculiar feature at this stage. Almost complete loss of the architecture of hepatopancreas was noticed and about 90 % of the hepatopancreatic tubules were found non–fuctional. The histopathological alteration in males was more pronounced than in females, both at acute and sub-acute exposure.