Time-course variations of DNA damage and biomarkers of oxidative stress in tilapia (Oreochromis niloticus) exposed to effluents from a swine industry.
DNA damage (Comet assay), lipoperoxidation levels (TBARS), and several biomarkers of oxidative stress such as catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPx), glutathione S-transferase (GST), and contents of reduced (GSH) and total (TG) glutathione were measured in liver and blood (Comet assay) of tilapia (Oreochromis niloticus) exposed for 7, 15, 30 (subchronic exposure), 60, and 90 days (chronic exposure) to two treatment lagoons of a swine-processing plant, the first an anaerobic lagoon and the second a final treatment lagoon. After the 15th day, TBARS increased in fish exposed to both lagoons, decreased on the 30th day, and on the 90th day remained similar to controls. Fish exposed subchronically and chronically to both effluents showed consistently greater DNA damage. The CAT and GPx activities showed similar profiles and were induced only during the first week and during the first and second months. GST activity was induced throughout the experimental period. On the other hand, GR activities showed inverted profiles, with progressively decreased activities in the liver of fish exposed to the anaerobic lagoon, and progressively increased activities in fish exposed to the final lagoon. GSH showed higher contents in liver after 60 and 90 days of exposure to the final lagoon. GSSG contents were higher in fish exposed to the final lagoon throughout the experimental period. After 15 days, tilapia exposed to both lagoons showed enhanced total glutathione contents. The hepatic antioxidant system and biomarkers of oxidative stress such as DNA fragmentation and TBARS contents of tilapia exposed to both lagoons presented biphasic profiles. These changes in the antioxidant status also indicate that the industrial treatment is not adequate to avoid damaging environmental effects.
Lima
P L
PL
Departamento de Ecologia e Zoologia, CCB, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil.
Benassi
J C
JC
Pedrosa
R C
RC
Dal Magro
J
J
Oliveira
T B
TB
Wilhelm Filho
D
D
D000818:Animals; D015415:Biomarkers / Q000097:blood*; D004249:DNA Damage; D005525:Food-Processing Industry; D008099:Liver / Q000378:metabolism; D018384:Oxidative Stress; D034421:Sus scrofa; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis; D017210:Tilapia / Q000502:physiology*; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D015415:Biomarkers; D017392:Thiobarbituric Acid Reactive Substances; D014874:Water Pollutants, Chemical