CHROMOSOMAL ABERRATIONS INDUCED BY A COMBINATION OF INDUSTRIAL CHEMICALS IN AFRICAN CATFISH (Clarias gariepinus) AT LETHAL AND SUBLETHAL LEVELS

Abstract

The aim is to assess the variation in the karyotype number of chromosomes in C. gariepinus and the genetic consequences of exposure to mixed industrial chemicals in the African Catfish, providing valuable information for environmental management, conservation, and potential human health considerations. From the acclimation tanks, ten healthy and active juveniles were randomly selected with five test concentrations: 0.0ml/l (control), 25ml/l, 50ml/l, 100ml/l, 150ml/l, 200ml/l, and 250ml/l for lethal, and 0.0ml/l (control), 12.8ml/l, 25.59ml/l, 38.39ml/l, 51.19ml/l, and 63.99ml/l. Chromosomal aberration studies were conducted on the fish samples after 4 and 28 days of exposure. The study examines the karyological and cellular content of Clarias gariepinus, revealing a consistent 2n = 56 karyotype across the fish. Variability in individual karyotypes suggests aneuploidy and genetic material loss during gametogenesis. In C. gariepinus exposed to lethal concentrations of mixed chemicals, significant karyotype variations have implications for genetic health and environmental impact. Changes in metacentric, submetacentric, subtelocentric, and acrocentric/telocentric chromosomes signal genetic instability, crucial for species integrity and resilience. Genetic alterations may adversely affect reproductive success, leading to abnormalities in gamete formation and reduced reproductive fitness. Sub-lethal exposure to the mixed induces alterations in the karyotype of C. gariepinus, despite a consistent diploid number of 56. As a result of exposure to the chemical (Xylene: Diesel), mutations may occur, potentially altering karyotype structure and disrupting division control. Sublethal and lethal concentrations cause genotoxic effects. Genetic diversity and health are affected by C. gariepinus populations. For long-term effects to be predicted, it is important to understand the consequences of karyotype changes in C. gariepinus to predict the genetic health of the population in the future.