Owing to increased surface photo oxidation property associated with the nanocrystalline form of ZnS, the dissolved oxygen content in water get reduced in a dose dependent manner from their normal values, when different concentrations of ZnS nanoparticles (NPs) with various sizes are exposed to the water. Therefore, the animals living in a habitat exposed to ZnS NPs are forced to live in a hypoxic atmosphere. The mechanism of acclimatization to this hypoxic atmosphere by an Indian minor carp Labeo bata, along with its liver morphology, haematological parameters and metabolic responses are studied systematically. During progressive hypoxia, the liver histomorphology of L. bata shows salient alterations from its normal tissue layout. Also a significant increase in the number density of red blood corpuscles (RBC) is documented for relatively smaller time (< 12 days) of ZnS NP exposure. Under hypoxial condition, haemoglobin and haematocrit concentrations are found to show a characteristic feature showing a peak value for exposure time of 9 days. Blood glucose and blood lactate levels of L. bata are found to vary in accordance with the varied physiological behaviour of the fish under ZnS NP exposure.
Key words: ZnS nanoparticles; hypoxia; acclimatization; Labeo bata