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

The palaemonid prawns Macrobrachium dayanum(Crustacea: Decapoda) are importantspecies found in river Gomti and are very good bioindicators. These prawns are ideal animals tostudy the histopathological impairments caused by the effect of heavy metals prominent in riverGomti. The test animals were exposed to LC50value (0.15 mg/l and 0.16 mg/l respectively)at acuteexposure for 24, 48,72 and 96h and at subacute exposure25% of 96hr LC50 values of CdCl2 for malesand females (0.0375mg/l & 0.04 mg/l) respectively for 10, 20 and 30 day exposure. Thehistopathological changes were studied in both the sexes in the animals.Marked histopathologicalchanges were noticed in hepatopancreas of M.dayanum after cadmium chloride exposure. At 96 hacute exposure, hepatopancreas showed vacuolization in epithelial cells, necrosis in tunica propria,increased number of migratory cells, granuloma in intertubular connective tissue alongwithkaryorrhexis and karyolysis in cells. Necrotic and degenerative changes in hepatopancreaticepithelium, which were mainly, noticed in R and B cells. Loss of histological architecture along withthe 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 changesat 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. Almostcomplete loss of the architecture of hepatopancreas was noticed and about 90 % of thehepatopancreatic tubules were found non–fuctional. The histopathological alteration in males wasmore pronounced than in females, both at acute and sub-acute exposure.