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.