Micronuclei are chromosome fragments or entire chromosomes that do not incorporate in the main nucleus of the cell, remaining in the cytoplasm after mitosis. Micronucleus tests are usually used to inquire the damage caused in DNA by different external factors. Roundup→ is the most common herbicide used in the world, and it has an active agent denominated glyphosate that can be responsible for increases of nuclear alterations. The herbicide is a product of Monsanto®, so it does not affect Soya RR, but in natural conditions it could contaminate the aquatic ecosystems and its living creatures. The objective of this work was to inquire the frequency of erythrocytes with micronuclei and other nuclear alterations in the fish Tilapia rendalli induced by the herbicide Roundup® in different concentrations (5 mg/L and 15 mg/L) throughout 5 and 10 days of exposure. The blood cells were coloured with 15% Giemsa for 15 minutes and the counting was made in an optical microscope. In the present study, the frequency of erythrocytes with micronuclei induced by Roundup® in the treatments are larger than those in the control but are not significant (p>0.05). However, when the other nuclei alteration frequencies were compared with control they demonstrated significant (p<0.05) quantities in the concentrations of 5 and 15 mg/L along 5 and 10 days of exposure.
Antonio Adami Pires, Renata Manelli-Oliveira and Julio Boschini-Filho