Effect of cadmium waterborne exposure on histological structure in gut tissue of mosquitofish gambusia affinis

In this study, cadmium (Cd) accumulation in mosquitofish G. affinis tissue and histological investigation of gut tissue was studied following water borne exposure. For this purpose fish were acutely exposed for 48 h to two concentrations of Cd (8 and 12 mgCdCl2/L). Following acute Cd-exposure, metal accumulation profiles differed between the two concentrations. Indeed, Cd content in fish tissue is concentration dependent manner. The Cd levels in control tissue differ significantly than group exposed to 8 and 12 mgCdCl2/L for 48 h and were respectively 0.67 ± 0.12, 3.03±1.19 and 30.14±19.18 μgCd/g of dw. Histopathological investigations revealed greater changes in gut G. affinis tissue. Following 48 h of exposure to 12 mgCdCl2/L, the most changes in gut tissue were characterized by infiltration of mononuclear leucocyte (IML) and eosinophils (LE) toward lamina propria following dilatation of blood vessels. After 96h of Cd exposure, histological lesions become more pronounced and include much degeneration of submucosa and a large number of goblet cells within villi were also observed. In addition, a reduction of the villi length and infiltration of leucocyte was also noted. The results showed that, freshwater fish, as the case of mosquitofish G. affinis, are sensitive to the presence of Cd in their environment and are able to accumulate it via a digestive tract.