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Hepatic lipid accumulation is ameliorated in obese KK mice by dietary sei whale oil


Whale oil (WO) contains n-3 polyunsaturated fatty acids (PUFAs), but the effects of whale oil intake on lipid metabolism have remained unclear. We examined the influence of WO on lipid metabolism in obese KK mice. Male KK mice were fed a high-fat diet for 12 weeks to induce obesity. The mice were then given free access to a different diet for 10 weeks: the lard/safflower oil (LSO) diet consisted of 25 energy% (en%) LSO (6:4), the WO diet consisted of 25 en% WO, and the fish oil (FO) diet consisted of 11 en% FO plus 14 en% LSO. The n-3 PUFA content of the FO diet was the same as that in the WO diet. In the WO and FO groups, the total plasma cholesterol level was significantly decreased compared with that in the LSO group. The number of lipid droplets in liver specimens was also lower in the WO and FO groups, and the hepatic triglyceride and total cholesterol levels were decreased in these groups compared with the LSO group. Hepatic mRNA levels of fatty acid synthase, and stearoyl-CoA desaturase 1, which are fatty acid synthesis-related genes, were decreased in the WO and FO groups. No significant differences were observed between the WO and FO groups. Taken together, these results indicate that WO intake inhibits lipid accumulation in the liver by reducing fatty acid biosynthesis.

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Acyl-coA carboxylase


Acyl-CoA oxidase


Carnitine palmitoyltransferase


Computed tomography


Cholesterol 7 α-hydroxylase


Docosahexaenoic acid


Docosapentaenoic acid


Diacron of reactive oxygen metabolites


Enzyme-linked immunosorbent assay


Icosapentaenoic acid


Fatty acid synthase


Fish oil






High-density lipoprotein


3-Hydroxy-3-methylglutaryl-coenzyme A


Lard/safflower oil


Medium-chain acyl-CoA dehydrogenase


Nonalcoholic fatty liver disease


Nonalcoholic steatohepatitis


Non-esterified fatty acid


Polymerase chain reaction


Phosphoenolpyruvate carboxykinase


Peroxisome proliferator-activated receptor


Polyunsaturated fatty acid


Stearoyl-CoA desaturase


Sterol regulatory element-binding protein


Carratelli units


Uncoupling protein


White adipose tissue


Whale oil


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We would like to thank NOF Corporation (Tokyo, Japan) for providing FO. This study was supported in part by Grant-in-Aid for Scientific Research on Innovative Areas (to S.S., Grant No. 22126004) and Grant-in-Aid for Young Scientists (B) (to S.H., Grant No. 90644261) from the Ministry of Education, Culture, Sports, Science and Technology of Japan.

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Correspondence to Seiji Shioda.

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This study was funded by Kyodo Senpaku Kaisha, Ltd, Tokyo, Japan.

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Hirako, S., Suzuki, M., Kim, H. et al. Hepatic lipid accumulation is ameliorated in obese KK mice by dietary sei whale oil. Fish Sci 82, 509–517 (2016).

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