Assessment of oxidatively generated DNA damage in rainbouw trout (Oncorhynchus mykiss) fed with different lipid sources

The formation of DNA adducts 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) and 1,N 6-etheno-2'-deoxyadenosine (εdAdo) in organs of rainbow trout fed with different lipid sources was investigated. Fish were fed for 16weeks with five experimental diets supplemented either with fish oil (FO), or one of four different vegetable oils: olive oil (OO), sunflower oil (SO), linseed oil (LO), and palm oil (PO). DNA adducts were measured by LC-ESI/MS/MS in the liver, spleen and kidney to evaluate DNA damage. The highest 8-oxodGuo levels were observed in liver and kidney of fish fed the FO diet (7814±678 and 13,554±1571 adducts/10 9 nucleosides, respectively), and in spleen of fish receiving the SO diet (13,541 adducts/10 9 nucleosides). The PO diet resulted in the lowest content of 8-oxodGuo in all tissues, 6720±652 adducts/10 9 nucleosides in liver, 8340±668 adducts/10 9 nucleosides in kidney, and 6202±1038 adducts/10 9 nucleosides in spleen. Similarly, εdAdo was highest in the FO treatment, 12.5±1.9 adducts/10 9 and 58.2±4.6 adducts/10 9 nucleosides in liver and kidney respectively, whereas SO produced the highest εdAdo value (568.2 adducts/10 9 nucleosides) in spleen. In spleen and kidney, εdAdo was lowest in the PO treatment (47.8 and 27.1±5.9 adducts/10 9, respectively). In liver, the OO diet registered the lowest εdAdo value (8.9±1.9 adducts/10 9 nucleosides).Significant positive correlations were observed between levels of 8-oxodGuo in kidney tissues and the amount of 20:4n-6, 20:5n-3, 22:6n-3, n-3 LC-PUFA and n-6 LC-PUFA intake (P< 0.05). The εdAdo levels in spleen tissue were correlated with 18:2n-6 and n-6 PUFA intake (P< 0.05).This study suggests that dietary lipids play an important role in the oxidatively generated damage to DNA in fish.