Volume 89, Issue 3, March (2003), pp. 429-437 © The Author 2003
doi:10.1079/BJN2002801

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Role of dietary fat type in the development of adiposity from dietary obesity-susceptible Sprague-Dawley rats

In Surk Jang^1,2,CA, Dae Yeon Hwang³, Kab Ryong Chae³, Ju Eun Lee³, Yong Kyu Kim³, Tae Seok Kang³, Jin Hee Hwang³, Chae Hyung Lim³, Young Bum Huh⁴ and Jung Sik Cho^3
1Department of Animal Science & Biotechnology, RAIRC, Jinju National University, Chilam-Dong 150, Jinju, KyeongNam, Korea
²Department of Animal Science & Biotechnology, RAIRC, Jinju National University, Chilam-Dong 150, Jinju, KyeongNam, Korea
³Laboratory Animal Resources, National Institute of Toxicological Research, Korea FDA, Nokbun-Dong, Eungpyung-Ku 5, Seoul, Korea
⁴Department of Anatomy, College of Medicine, Kyunghee University, Hoeki-Dong 1, Dongdaemum-Ku, Seoul, Korea

 (Received 19 April 2002–Revised 30 September 2002–Accepted 31 October 2002)

The present study was designed to define how dietary fat type regulates body adiposity in dietary obesity-susceptible (DOS) Sprague–Dawley (SD) rats. Eighty-three SD rats received a purified diet containing 50g maize oil (MO)/kg for 3 weeks and then thirty-nine of the rats, designated as the DOS rats, were allotted to diets containing 160g MO (DOS-MO), beef tallow (DOS-BT) or fish oil (DOS-FO)/kg for 9 weeks. As a result of the experiment, the DOS-FO rats had significantly (P<0·05) reduced weight gain and abdominal and epididymal fat-pad mass than the DOS-MO and DOS-BT rats. Serum leptin level was also significantly (P<0·05) lower in the DOS-FO rats; however, hypothalamic leptin receptor (a and b) mRNA and neuropeptide Y expressions were not altered by dietary fat sources. A lower acetyl-CoA carboxylase mRNA expression in the liver was observed in the DOS-FO group, whereas hepatic peroxisome proliferator-activated receptor-g mRNA and protein expressions were markedly elevated in the DOS-FO group compared with those in the other groups. We did not observe differences in acetyl-CoA carboxylase and peroxisome proliferator-activated receptor-g expressions in epididymal fat of the DOS rats consuming MO, BT or FO. It is concluded from our present observations that dietary fat type, especially that rich in FO, plays a potential role in down-regulation of adiposity by altering hepatic lipogenic genes, rather than feeding behaviour, in the DOS-SD rats.

Abbreviations: ACC; acetyl-CoA carboxylase; BT; beef tallow; DOS; dietary obesity-susceptible; FO; fish oil; MO; maize oil; NPY; neuropeptide Y; Ob-R; hypothalamic leptin receptor; PPARg; peroxisome proliferator-activated receptor-g; SD; Sprague–Dawley

Keywords:
Fat type, Leptin, Hypothalamic leptin receptor, Neuropeptide Y, Acetyl carboxylase CoA, Peroxisome proliferator-activated receptor-g