Micronucleus test in the peripheral erythrocytes of the exotic fish, Oreochromis mossambica

Abstract

The micronucleus test, principally followed in mammals has been conducted in the peripheral erythrocyte of blood smears of the fresh water exotic fish, Oreochromis mossambica, in separate sets after treatments with an antimetabolite chemosterilant, d-glucosamine hydrochloride, an organochloride insecticide, aldrin, a heavy metallic compound, cadmium chloride, and X-rays. The blood smears were stained generally in Leishman followed by Geimsa and sometimes Feulgen. The affected erythrocytes of different treated specimens showed the occurrence of roundish micronucleus in the cytoplasm close to or completely free from the main nucleus, but the frequency was not very high. The micronuclei were absent in the control series. The frequency of the chromosome aberrations induced by the same dose of X-rays in the gill epithelia was much higher than that of micronucleus in the peripheral erythrocytes. In spite of limitations the micronucleus test in the peripheral blood of fishes is the quickest means of evaluating genotoxic agents in aquatic environment.