Dietary Olive and Perilla Oils Affect Liver Mitochondrial DNA Methylation in Large Yellow Croakers

Background: Substantial progress has been made in nutritional epigenetics, but little is known regarding whether mitochondrial DNA (mtDNA) methylation is involved in this process. Objective: The objective of this study was to determine whether dietary lipid sources [various fatty acids (FAs)] modify mtDNA methylation. Methods: A total of 600 large yellow croakers (Larimichthys crocea) with an average initial weight of 151 +/- 4 g were fed 1 of 5 diets (3 replicate cages/treatment) containing either fish oil (FO) (control), palmitic acid, olive oil (OO), sunflower oil, or perilla oil (PO) as the dietary lipid source (12% dry weight of the diet) for 70 d. Pyrosequencing was used to determine the effects of dietary lipid sources (FAs) on mtDNA methylation. Results: Mitochondrial arginine transfer RNA and NAD(H) dehydrogenase 4L encoding region methylation in the liver was higher in the OO (9.5% +/- 0.52%; P < 0.05) and PO (7.3% +/- 0.33%; P < 0.05) groups than in the FO (5.9% +/- 0.42%) group, whereas 12S ribosomal RNA (rRNA) methylation in the liver was lower in the OO group (2.7% +/- 0.22%) than in the FO group (4.2% +/- 0.73%) (P < 0.05). Additionally, fish fed the OO diet had lower liver mRNA levels of ND3 (P < 0.05), ND4L (P < 0.05), ND6 (P < 0.05), 12S rRNA (P < 0.05), and 16S rRNA (P < 0.05) than those fed the FO diet, whereas fish fed the PO diet had lower liver mRNA levels of 16S rRNA than those fed the FO diet (P < 0.05). Moreover, fish fed the OO (P < 0.05) or PO (P < 0.05) diet had lower liver mitochondrial complex I activity than did those fed the FO diet. Conclusions: These findings provide the first evidence, to our knowledge, that dietary lipid sources influence mitochondrial function through mtDNA methylation in large yellow croakers.