IMPACT OF DIFFERENT DIETARY FATTY-ACIDS ON PLASMA AND LIVER LIPIDS ISINFLUENCED BY DIETARY-CHOLESTEROL IN RATS

The purpose if this study was to determine blood and liver responses i n rats to stepwise replacement of palm oil with high-oleate lipids wit h and without dietary cholesterol. Two 28-day experiments were conduct ed in which 12% fat (wt/wt) was fed to rats in diets containing 0 (EXP 1) or 0.4% cholesterol (EXP2). Nine diets were compared in each experi ment; 12% palm oil was replaced in 3% increments by a high-stearate li quid (five treatments); 6% palm oil combined with 6% high-oleate saffl ower oil, 12% tallow; and 12% corn oil. Gain:consumption ratios were l ower when rats were fed high-stearate fats. Plasma and liver cholester ol were greater when rat were fed 0.4% cholesterol (EXP2 compared with EXP1). The tallow diet produced the lowest plasma cholesterol in EXP1 , but the highest level in EXP2. Similar plasma cholesterol levels occ urred for groups fed 12% palm oil, and safflower oil, with or without dietary cholesterol. In EXP1, dietary treatments had little effect on liver cholesterol. In EXP2, liver cholesterol decreased as consumption of the high-stearate fat increased, and was highest with 12% safflowe r oil. Proportion of hepatic fatty acids generally reflected intake; h owever, greater (16:1 and 18:1) and lower (18:0 and 20:4) occurred in cholesterol-supplemented rats (EXP2 compared to EXP1). In conclusion, rat plasma and liver liquid responses to different dietary fats are af fected to dietary cholesterol, the presence of which greatly increases liver cholesterol, liver total fat, and tallow-induced hypercholester olemia.