Quantification histopathological analysis in the gills of carp fish exposed to sub lethal concentration of nano zinc oxide

الملخص EN

Nano-zinc oxide ranks third in the world in production, as it is used in many industries, enters the aquatic environment directly or indirectly, and is considered one of the most toxic substances for aquatic organisms.

Therefore, these studies aimed to determine the toxic effect of the sublethal concentration of N-ZnO on the gills of carp fish that were treated for 7, 14, 21, 28, 35, and 42 days and using a semi-quantitative evaluation protocol for histopathological alteration.

The histopathological alteration involved circulatory changes, cell growth disturbances, and morphological changes, the most severe lesion occurred on day 35 of treatment, and the occurrence of necrosis and death of the gill tissue at day 42 of the treatment, which was more significant for morphological changes when compared with the other lesion and period.

The results showed that the histopathological changes on the seventh day of treatment were severe lesions, while in the rest of the treatments, they were irreversible lesions.

It is concluded from this study that the gills are a good bio-indicator for evaluating the pollution status of the aquatic environment and that the sub-lethal concentration of N-ZnO leads to pathological changes in the gills and the possibility of using semi-quantitative assessment and statistical analysis to give significance for the most severe pathological lesions.