British Journal of Nutrition

Full Papers

Molecular Nutrition

Role of hepatic de novo lipogenesis in the development of fasting-induced fatty liver in the American mink (Neovison vison)

Kirsti Rouvinen-Watta1 c1, Lora Harrisa1, Morag Dicka1, Catherine Pala1, Sha Leia1a2, Anne-Mari Mustonena3a4 and Petteri Nieminena3a4

a1 Department of Plant and Animal Sciences, Nova Scotia Agricultural College, PO Box 550, Truro, NS, Canada B2N 5E3

a2 Department of Bioscience and Biotechnology, Dalian University of Technology, Dalian 116024, People's Republic of China

a3 Institute of Biomedicine/Anatomy, Faculty of Health Sciences, School of Medicine, University of Eastern Finland, PO Box 1627, Kuopio FI-70211, Finland

a4 Department of Biology, Faculty of Science and Forestry, University of Eastern Finland, PO Box 111, Joensuu FI-80101, Finland

Abstract

American mink (Neovison vison) develop fatty liver quickly in response to food deprivation, which results in preferential mobilisation of n-3 PUFA. The altered n-3:n-6 PUFA ratio in the liver may activate the endocannabinoid system resulting in increased lipid synthesis. The objective of the present study was to investigate the effects of feeding intensity (80 or 120 % RDA), dietary fat source (n-3, n-6 or n-9 fatty acids (FA)) and short-term fasting (1–7 d) on hepatic de novo lipogenesis (DNL) and the development of fatty liver in mink. Significantly elevated expression of mRNA encoding for acetyl-CoA carboxylase-1 (ACC-1) and FA synthase (FAS) was observed in the liver of mink fasted for 5–7 d, while upon re-feeding for 28 d after a 7 d food deprivation, DNL returned to pre-fasting levels. The females had a higher expression of ACC-1 and FAS mRNA than the males. In the non-fasted animals, dietary fat source and feeding intensity had significant effects on ACC-1 mRNA. The highest levels were observed in the mink fed the rapeseed oil (n-9) diet at 80 % RDA, while the lowest levels were seen when the same diet was fed at 120 % RDA. For FAS, the highest gene expression was seen in the fasted mink fed at 80 % RDA and the lowest in the non-fasted mink fed at 80 %. It is concluded that short-term food deprivation induces hepatic lipidosis in mink and that during this process, hepatic DNL further exacerbates liver fat accumulation.

(Received August 09 2011)

(Revised October 20 2011)

(Accepted November 10 2011)

(Online publication January 03 2012)

Key Words:

  • Acetyl-CoA carboxylase;
  • De novo lipogenesis;
  • Fatty acid synthase;
  • Hepatic lipidosis;
  • Hepatic steatosis

Correspondence:

c1 Corresponding author: Dr K. Rouvinen-Watt, fax +1 902 895 6734, email krouvinen@nsac.ca

Footnotes

  Abbreviations: ACC-1, acetyl-CoA carboxylase-1; BW, body weight; DNL, de novo lipogenesis; FA, fatty acid; FAS, fatty acid synthase; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; HPRT1, hypoxanthine phosphoribosyltransferase 1; LC-PUFA, long-chain PUFA; NAFLD, non-alcoholic fatty liver disease; RT-qPCR, quantitative real-time PCR; SREBP, sterol regulatory element-binding protein

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