Vol. 1, Issue 8, Part I (2015)

Abstract
Nanoparticles are particles with one or more dimesnsions in the nanoscale range of 1-100nm. The ZnO NPs are characterized by XRD studies. Three different concentrations (30, 50 and 70ppm) of ZnO NPs are exposed to Oreochromis mossambicus. The general activity, social interaction and maintenance behaviour are severly disturbed in all treated groups especially in higher concentration (70ppm). Various tissues such as gill, muscle, brain, intestine and ovary are dissected out and histological analysis are performed. ZnO NPs treated gill tissues showed Necrotic lamella (NL), lamellar fusion (LFU), Abnormal Gill tip (AG), Proliferation of Chloride cells (PCC), excessive mucous formation (MU). Treated Muscle tissues showed Necrotic striated muscle (NSM), necrotic muscle fibres (NMF), shrinkage of muscle fibres. Vacoules (V) formation, Enalargement of Pyramidal cells (EPC) and necrosis are obsered in treated brain cells. Treated Intestinal tissues showed swollen goblet cells (SG), occurrence of Hyperplasia (H) and necrotic condition. Degenerated Late Vitellogenic oocytes (DLV) and formation of Vacuolation (V) and necrotic oocytes are observed in treated ovary tissues. Exposure of ZnO NPs disturbs the behavioural activity and degenerate various organs of the freshwater fish O. mossambicus.