The objective of this study was to evaluate the possible histopathological and some serum biochemical effects of frequently used triazophos (O, O-diethyl O-1phenyl-1 H-1, 2, 4- triazol-3-yl phosphorothioate), an organophosphate insecticide in avian species. For this purpose a total of 60 adult Japanese quail were randomly allocated to five equal groups (A-E) having 12 birds each. All the birds in experimental groups were orally administered triazophos @ 0, 2, 4, 6 and 8 mg/kg BW daily for 48 days. The blood and morbid tissues were collected at day 16, 32 and 48 of the post treatment. Grossly, kidneys, lungs, spleen and heart of birds received higher concentration of triazophos (8 mg/kg BW) were swollen and congested. No significant change was observed in relative weight of bursa, trachea and proventriculus. However, the relative weight of spleen, kidneys and lungs was significantly increased while the relative weight of heart significantly decreased as compared to control group. Serum urea, creatinine, cardiac enzymes (CPK and CK-MB) were significantly increased while total proteins decreased in treated birds. Histologically, mild congestion, hypertrophied glomeruli, detachment of renal tubules, tubular necrosis, atrophied Bowman's spaces and pyknotic nuclei of epithelial cells in tissue sections of kidneys were observed. Heart tissues showed degenerating cardiac muscle fibers along with loss of transverse striations. Bursa of Fabricius in treated birds showed severe cytoplasmic vacuolation. Congestion in lungs and spleen was also observed at higher concentrations of insecticide. The present study revealed for the first time that triazophos causes histo-architectural and serum biochemical changes in birds in proportion to dose and duration.

Key words: Quail, Triazophos, Tissue changes, Serum biochemistry