The effect of hypoxia on Nile tilapia, Oreochromis niloticus for one day (trial 1) and for 30 days (trial 2) was studied. The hypoxic oxygen concentrations used in the two trials were 2, 1, and 0.5 mg O2 L-1 in comparison to control normoxic group 7 mg O2 L-1. The assayed enzymes were: superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione S-transferase (GST), glutathione reductase (GR), γ-glutamyl cysteinyl synthetase (γ- GCS), and γ- glutamyl transpeptidase (γ-GT). The activities of the enzymes assayed were significantly increased in liver and white muscle of fish exposed to both short term and long term of hypoxia exposures, except in white muscle of fish exposed to 2 and 1 mg O2 L-1. The changes in these parameters were intensified at low levels and of long hypoxia exposure. The significance of these alterations in enzyme activities is discussed.
Key words: Antioxidant Enzymes, Nile Tilapia, Liver, White Muscle, Hypoxia
|
