Induction of micronuclei and other nuclear abnormalities in peripheral erythrocytes of Nile tilapia, Oreochromis niloticus, following exposure to sublethal cadmium doses

Abstract

Th e genotoxic eff ects of sublethal doses of cadmium in peripheral erythrocytes of Oreochromis niloticus was investigated using micronucleus (MN) and nuclear abnormalities (NAs) tests. For this reason, the fi sh were exposed to medium changes of 0.5 and 1.0 mg/L doses of cadmium (Cd) during an average treatment period of 10 days. On the 2nd, 4th, 6th, and 10th days of the test period, the erythrocytes, including the micronuclei (MN) and other nuclear abnormalities such as lobbed nuclei (LB), blebbed nuclei (BL), and notched nuclei (NT), were counted and pointed out. As a positive control, a 4 mg/L dose of cyclophosphamide was used. Exposure to doses of cadmium caused signifi cantly increased (P < 0.05) micronuclei in peripheral erythrocytes of fi sh. It was also observed that the application of a 1.0 mg/L dose of Cd produced more of an eff ect on MN frequencies than the application of a 0.5 mg/L dose. Th e maximum frequencies of MN were recorded on the fourth day of the experiment period. Exposure to doses of cadmium caused signifi cantly increased (P < 0.05) NA (LB, BL, and NT) frequencies and, as with the MN results, the 1.0 mg/L dose of Cd had more of an eff ect than the 0.5 mg/L dose on NA frequencies. Th e maximum frequencies of NAs were recorded on the fourth day of the experiment. As a result of these doses of Cd, the MN and NA frequencies in peripheral erythrocytes of fi sh were observed to increase in relation to both the time and dose applied. However, a gradual trend of decrease was also observed starting from the sixth day. © TÜBİTAKV.