title: Genotoxicity assessment and oxidative stress responses in freshwater African catfish Clarias gariepinus exposed to fenthion formulations.
abstract: Fenthion is one of the most widely used organophosphate insecticides for the control of many varieties of pests in Nigeria. The genotoxic effect of the pesticide was evaluated in the blood erythrocytes of Clarias gariepinus using the micronucleus (MN) test. The oxidative stress parameters were also studied in the liver and gill tissues. Fish were exposed to 2.0, 4.0, and 8.0 mgL-1of fenthion and sampling was done on days 1, 7, 14, 21 and after 7-day recovery. Micronuclei induction was highest (7.55) on day 14 at all concentrations in the peripheral blood cells. Oxidative stress was evidenced by increased lipid peroxidation (LPO). Maximum LPO values of 62.47% and 71.17% were observed in the gill and liver tissues respectively in C. gariepinus exposed to 8.0 mgL-1concentration of fenthion. There were alterations in the values of reduced glutathione (GSH), glutathione reductase (GR), glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) during the exposure and recovery periods. The 7-day recovery period was not adequate to eliminate fenthion-induced changes as LPO, CAT, and GR activity remain elevated. However, MN frequency and activity of SOD, GSH, and GPx (except at 8.0 mgL-1) recovered. The present findings give further credence on the integrated use of MN test and oxidative stress parameters in risk assessment of pollutants in aquatic ecosystem.
authors.affiliation: a Molecular Biology and Biotechnology Division, Department of Zoology and Environmental Biology, University of Nigeria Nsukka , Nigeria.
authors.forename: Christopher Didigwu
authors.initials: CD
authors.lastname: Nwani
authors.affiliation: b Department of Biological Science , Federal University Lokoja , Nigeria.
authors.forename: Peace Onas
authors.initials: PO
authors.lastname: Somdare
authors.affiliation: c Department of Biology , Microbiology and Biotechnology, Federal University Ndufu-Alike , Ikwo , Nigeria.
authors.forename: Emmanuel Okechukwu
authors.initials: EO
authors.lastname: Ogueji
authors.affiliation: d Department of Crop Science and Land Scape Management , Ebonyi State University Abakaliki , Nigeria.
authors.forename: Jacinta Chinedu
authors.initials: JC
authors.lastname: Nwani
authors.affiliation: e Department of Vocational Teacher Education , University of Nigeria Nsukka , Nigeria , and.
authors.forename: Juliana Adimonye
authors.initials: JA
authors.lastname: Ukonze
authors.affiliation: f Department of Plant Science and Biotechnology , University of Nigeria Nsukka , Nigeria.
authors.forename: Alfreda O
authors.initials: AO
authors.lastname: Nwadinigwe
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D002397:Catfishes / Q000097:blood* / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D004912:Erythrocytes / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D005284:Fenthion / Q000737:chemistry / Q000633:toxicity*; D005618:Fresh Water / Q000737:chemistry; D007306:Insecticides / Q000737:chemistry / Q000633:toxicity*; D048629:Micronuclei, Chromosome-Defective / Q000139:chemically induced* / Q000706:statistics & numerical data; D015162:Micronucleus Tests; D009153:Mutagens / Q000737:chemistry / Q000633:toxicity*; D009549:Nigeria; D018384:Oxidative Stress / Q000187:drug effects* / Q000235:genetics; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000633:toxicity*
chemical_list: D000975:Antioxidants; D007306:Insecticides; D009153:Mutagens; D014874:Water Pollutants, Chemical; D005284:Fenthion
keywords: Clarias gariepinus; Fenthion; lipid peroxidation; micronuclei; oxidative stress