Temperature shock is a major natural cause of mass mortality of global fish. Nile tilapia Oreochromis niloticus, one of the most widely cultured species, with high resistance against severe environmental conditions, is also affected by rapid temperature changes. This research was conducted to investigate histopathological changes and oxidative stress in O. niloticus in response to temperature shock. The malondialdehyde levels in the serum, gills and brain, the histopathology of the gills and brain, and the histochemical characterization of the gills’ mucosubstances were measured in the fish exposed to heat shock and cold shock conditions. The results showed that the fish could not survive under 37 °C for 24 hours. Malondialdehyde levels in the gills, brain and serum increased significantly when compared to those of the controls. Moreover, histopathological changes and a decrease in the number of neutral and acidic mucous cells was observed in the gills of fish in both the heat shock and cold shock groups. Histopathological alteration, vacuolated neuropil in the brain, was observed only in the fish in the cold shock groups. The results from this study indicate that rapid 4 °C changes in water temperature (25–21 and 25–29 °C) evoked oxidative stress and histological damage to O. niloticus, whereas extreme 12 °C changes (25–13 and 25–37 °C) severely affected their oxidative stress and histopathological condition.

温度冲击是全球鱼类大量死亡的主要原因。尼罗罗非鱼Oreochromis niloticus是养殖最广泛的物种之一，对严酷的环境条件具有很高的抵抗力，也受到温度快速变化的影响。进行这项研究以调查尼罗罗非鱼的组织病理学变化和氧化应激应对温度冲击。在暴露于热激和冷激条件下的鱼中，测量其血清，腮和脑中丙二醛的水平，腮和脑的组织病理学以及腮中粘膜物质的组织化学特性。结果表明，该鱼在37°C下无法存活24小时。与对照组相比，腮，大脑和血清中的丙二醛水平显着增加。此外，在热休克和冷休克组中，在鱼the中均观察到组织病理学变化以及中性和酸性粘液细胞数量的减少。仅在冷休克组的鱼中观察到组织病理学改变，即脑中空泡化的神经pil。尼罗罗非鱼（O. niloticus），而12°C的极端变化（25-13和25-37°C）严重影响了它们的氧化应激和组织病理学状况。