Micronucleus test in fish genome: A sensitive monitor for aquatic pollution

Abstract

The aquatic environment makes up the major part of our environment and resources, therefore its safety is directly related to the safety our health. In this study, three tilapia species (Oreochromis niloticus, Oreochromis aureus and Tilapia zilli) and Clarias gariepinus were employed to estimate water pollution using micronucleus (MN) test. The test has been used successfully as a mutagenic assay. It is simple, reliable, sensitive, and it does not depend on any karyotypic characteristics. Fish were collected from locations that display differential environmental stresses. Two main experiments were carried out. In the first one, blood samples were collected, fixed for 24 h and then were stained with Giemsa. In the second experiment, fish were acclimated for a week. Fish were fed and each specimen had received an IP injection of cyclophosphamide (2.6, 10, 40, mg/kg b.wt). After 24 h, blood samples were collected and MN frequencies were counted and statistically tested. Results from this study recommend the use of the micronucleus test in fish erythrocytes as a sensitive monitor for aquatic pollution. The results show also that the assay can be employed for the evaluation and the assessment of water pollution and aquatic mutagens.