سعید حاجی رضایی

The potentials of gingko, Ginkgo biloba extract in ameliorating the toxicity of titanium nano-oxide (NanoTiO2) (30% of the LC50 or 1.65 mg/l) were evaluated in the rainbow trout, Oncorhynchus mykiss. Fish (n = 540; mean weight: 22.5 ± 2.1 g) were distributed into 18 tanks (n = 30/tank). The test treatments were: negative control (NC): non-supplemented and non-exposed fish, positive control (PC): non-supplemented fish exposed to 1.65 mg/ l nano TiO2, G1 + Ti: 0.5 g GIB/kg + 1.65 mg/l nano TiO2, G2 + Ti: 1 g GIB/kg + 1.65 mg/l nano TiO2, G3 + Ti: 2 g GIB/kg + 1.65 mg/l nano TiO2, G4 + Ti: 4 g GIB/kg + 1.65 mg/l nano TiO2. The experiment was done during 60 days. The nano-TiO2 treatments showed lower growth performance (P < 0.05) in comparison with nonexposed fish. Protease and lipase activities mainly decreased (P < 0.05) in response to nano TiO2 in the treatments, G1 + Ti and G4 + Ti compared to NC. The immunity was depressed (P < 0.05) in PC and fish of G1 + Ti and G4 + Ti compared to NC, G2 + Ti and G3 + Ti. Exposure to nano-TiO2 stimulated liver antioxidant enzymes almost all in PC and fish of the groups, G1 + Ti, G2 + Ti, G4 + Ti compared to NC (P < 0.05). Total antioxidant capacity (TAC) elevated the treatments, G2 + Ti and G3 + Ti (P < 0.05). 1–2 g GIB/kg ameliorated the oxidative stress and reduced malondialdehyde (MDA) levels in these treatments (P > 0.05). The liver metabolic enzymes mainly increased in serum, following Nano-TiO2 exposure in PC and treatments, 0.5–1 g GIB/ Kg (P < 0.05). Nano-TiO2 caused liver and intestine lesions mostly in PC and fish of 0.5 g GIB/kg. In conclusion, our results indicated that GIB at levels of 1–2 g GIB/kg can ameliorate nano-TiO2 –induced oxidative atress and its adverse effects on immunity and liver function in the fish.