Effects of sub lethal concentrations of nickel and copper on histopathological lesions of gill tissue in Kutum fry Rutilus kutum (Kamensky, 1901)R. kutum, Histopathology, Gill, Heavy metals

The present study aims at investigating the Histopathological effects of nickel and copper on the gill of Kutum Rutilus kutum. To perform this study, 120 pcs kutum were caught from Syjval fish reproduction center (Bndar-turkmen) with average length of 25/0 ± 5/4°meters and average weight of 1 ± 1/1gram. After the compatibility of the sample with laboratory conditions, the experiment was conducted in 30 days at concentrations of (CuCl2 1.3 mg/L and NiCl2 3.9 mg/L) in the aquarium with the dimensions 65 × 30 × 40 cm. Heavy metal concentrations in water solution was renewed every 48 and the tissue samples were caught during three periods of 7, 15 and 30 days. Results indicate that with the increase of exposure time to copper, damage to gill tissue, such as hyper-emia and hemorrhage, fractures and connectivity of secondary lamella and secondary lamella shortening, blade gill, lamella of swollen multi-cellular were more severe. Regarding Ni, the increase in mucus secretion and hyperemia resulted in secondary lamella fusion and hypertrophy. In sum, The amount of damage gill tissue in different concentrations of Cu was more than Ni.