Free Access
Reprod. Nutr. Dev.
Volume 45, Number 4, July-August 2005
Page(s) 405 - 418
Reprod. Nutr. Dev. 45 (2005) 405-418
DOI: 10.1051/rnd:2005037

Dose effect of alpha-linolenic acid on lipid metabolism in the hamster

Anne Morisea, Jacques Mourotb, Michel Riottota, Pierre Weillc, Evelyne Fénartd and Dominique Hermiera, e

a  Laboratoire de Physiologie de la Nutrition, Bât. 447, Université Paris-Sud, 91405 Orsay Cedex, France
b  INRA, SENAH, Saint-Gilles, 35590 L'Hermitage, France
c  Valorex, La Messayais, 35210 Combourtillé, France
d  ONIDOL, 12 avenue George V, 75008 Paris, France
e  Present address: UMR Physiologie de la Nutrition et du Comportement Alimentaire, INA-PG, 16 rue Claude Bernard, 75231 Paris Cedex 05, France

(Received 22 July 2004; accepted 31 January 2005)

Abstract - In order to meet dietary requirements, the consumption of $\alpha$-linolenic acid (ALA, 18:3 n-3) must be promoted. However, its effects on triglyceride (TG) and cholesterol metabolism are still controversial, and may be dose-dependent. The effects of increasing dietary ALA intakes (1%, 10%, 20% and 40% of total FA) were investigated in male hamsters. ALA replaced oleic acid while linoleic and saturated FA were kept constant. Triglyceridemia decreased by 45% in response to 10% dietary ALA and was not affected by higher intakes. It was associated with lower hepatic total activities of acetyl-CoA-carboxylase (up to -29%) and malic enzyme (up to -42%), which were negatively correlated to ALA intake (r2 = 0.33 and r2 = 0.38, respectively). Adipose tissue lipogenesis was 2-6 fold lower than in the liver and was not affected by dietary treatment. Substitution of 10% ALA for oleic acid increased cholesterolemia by 15% but, as in TG, higher ALA intakes did not amplify the response. The highest ALA intake (40%) dramatically modified the hepatobiliary metabolism of sterols: cholesterol content fell by 45% in the liver and increased by 28% in the faeces. Besides, faecal bile acids decreased by 61%, and contained more hydrophobic and less secondary bile acids. Thus, replacing 10% oleic acid by ALA is sufficient to exert a beneficial hypotriglyceridemic effect, which may be counteracted by the slight increase in cholesterolemia. Higher intakes did not modify these parameters, but a very high dose resulted in adverse effects on sterol metabolism.

Key words: $\alpha$-linolenic acid / oleic acid / lipogenesis / cholesterol / triglyceride / bile acid / hamster

Corresponding author: Dominique Hermier

© INRA, EDP Sciences 2005