Cytogenetical studies on some River Nile species from polluted and nonpolluted Aquatic habitats

Abstract

Shanawan drainage canal is one of the many drainage canals present in Menufiya province, Egypt. It receives sewage water from Kafr Shanawan drainage canal. Also, it receive illegal run–off from sewage and wastes besides sewage of Shebeen Al-koom city. This study is aimed to investigate the frequency of chromosomal damage by using chromosomal aberrations test of head kidney cells in Oreochromis niloticus and Tilapia zillii fish. The study was performed on 5 groups of fish, control and four polluted groups. A and B stations are located before the source of sewage discharge while C and D stations are located after the source of sewage. In each group cytological studies were performed. Fishes caught from areas before the sources of sewage showing different types of chromosomal aberrations, including centromeric attenuations, chromatid breaks, chromatid gabs, chromatid deletion, centric fusion and fragmentation. The total aberrations were more obvious among the fishes of the areas after the source of sewage than those of the areas before the source of sewage. It was noted that O. niloticus is more sensitive to the effect of pollution than T. zillii. Cytogenetic Studies of the current Work could be used as criteria for pollution intensity, which can be used to avoid its toxic effect on aquatic environment.