Influence of dietary fish oil supplementation on DNA damage in peripheral blood lymphocytes of nine healthy dogs

Abstract

Background: Fish oil (FO) supplementation as a source of omega 3 fatty acids is associated with beneficial effects on health. However, high unsaturated fatty acid content in thediet could result in increased lipid peroxidation and damage to proteins, lipids and DNA.We evaluated the effect of dietary FO supplementation on DNA damage in peripheralblood lymphocytes of dogs. Additionally, we determined the effect of FO supplementation on lipid peroxidation and lipid profile of these dogs. Methods: Healthy male dogs (n = 9) were randomly assigned to one of two diets during90 days: control (CG, n = 4), based on a commercial food, and FO (FOG, n = 5), thesame food supplemented with 1000 mg FO. Blood samples were collected on days −1,30, 60 and 90. DNA damage was assessed with the comet assay, and the damage indexwas obtained. Malondialdehyde (MDA) levels were determined as an indicator of lipidperoxidation. Lipid profile determination included serum triglyceride, cholesterol, lowdensity lipoprotein and high-density lipoprotein levels (HDL). Results: Damage index values (arbitrary units) were lower in FOG on day 30 (CG,13.7 ± 2.5; FOG, 6.5 ± 2.5), 60 (CG, 14.7 ± 2.5; FOG, 3.5 ± 2.5) and 90 (CG, 15.5 ±2.5; FOG, 3.0 ± 2.5) compared with CG (treatment × time interaction, p < 0.01). Serum MDA and HDL concentrations were lower in FOG compared with CG on day 60 and90 (treatment × time interaction, p < 0.05). Conclusion: These findings suggest that dietary FO supplementation did not induceDNA damage in peripheral blood lymphocytes of healthy dogs, but rather reduced it.