Table of Contents
Journal of Histology
Volume 2014, Article ID 190139, 11 pages
Research Article

Alterations in the Gill Filaments and Secondary Lamellae of Cirrhinus mrigala Exposed to “Nuvan,” an Organophosphorus Insecticide

Skin Physiology Laboratory, Centre of Advanced Study, Department of Zoology, Banaras Hindu University, Varanasi 221 005, India

Received 30 June 2014; Revised 18 September 2014; Accepted 3 October 2014; Published 27 October 2014

Academic Editor: Victor H. Casco

Copyright © 2014 Nidhi Srivastava et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The alterations in the epithelium of the gill filaments and the secondary lamellae of the gills of Cirrhinus mrigala, on exposure to “Nuvan,” have been explored in the present investigation using light and scanning electron microscopy. The fishes were exposed to two sublethal concentrations, 5 mg/L and 15 mg/L, of “Nuvan.” The changes are more rapid and intensive at higher concentration than at lower concentration, suggesting that the changes are dose dependent. Increase in thickness of epithelium covering secondary lamellae, merger of epithelium of gill filaments and adjacent secondary lamellae, and aneurysm is considered to reduce efficiency of gills for gaseous exchange. A significant decline in the density and area of the mucous goblet cells in the epithelium of the gill filaments and the secondary lamellae of C. mrigala exposed to “Nuvan” could be correlated with excessive loss of the secretory contents of these cells, uncompensated by their production in sufficient quantities. The histopathological changes, in general, take longer time to recover in the fishes exposed to 15 mg/L than those exposed to 5 mg/L indicating that the changes in fishes exposed to higher concentration are more severe than those at lower concentration of the insecticide.