Preeta Shakunta & G. K.Thakurb*
aDepartment of Zoology, T.M. Bhagalpur University, R-1. University Teachers Colony, Lalbagh, Sarai, Bhagalpur, 812002
bP.G. Department of Zoology, S.K.M. University, Dumka, Jharkhand
Received 6th May, 2008 ; Revised 18th August, 2008
Abstract : In present investigation urea induced pathological changes were observed in the histology and surface ultra structure of olfactory organ of an air breathing fish, Channa punctatus. Histopathological changes induced by urea are separation of basal layer from central core, necrosis and erosion of superficial layer, hypertrophy, degeneration and appearance of gaps in the outer and middle layers of olfactory epithelium. Under SEM, the surface of the olfactory lamellae of urea exposed fishes appeared to have shrunken and many ridges and grooves were noticed. Lamellar damage and many ciliated sensory cells have also been found to be present on the surface of the lamellae with patch like non sensory zones. These changes might be altering the sensitivity of smell in toxicant exposed fishes.