Dietary fat type related changes in tissue cholesterol and fatty acid synthesis are influenced by energy intake level in rats.
OBJECTIVE
To investigate the interaction of dietary fat source and energy intake level on tissue cholesterol and triacylglycerol fatty acid (TG-FA) synthesis.


METHODS
Ninety-six rats were randomly divided into 12 groups and fed diets containing fish oil, safflower oil, olive oil or beef tallow, each consumed ad libitum and at 85% and 68% of ad libitum intake for 10 weeks. Cholesterol and TG-FA fractional and absolute synthesis rates in the liver and fractional synthesis rates in the small intestine were determined using deuterium (D) incorporation 2 hours after injecting D2O.


RESULTS
Olive oil feeding was associated with higher (p < 0.05) cholesterol and TG-FA synthesis rates in the liver and small intestine compared with other fats. Modifications in cholesterol synthesis by fat type depended on energy intake level. With ad libitum feeding, synthesis rates were lower (p < 0.01) following the safflower oil vs. the olive oil treatment. This effect was not observed in 68% energy restricted animals. However, in the intestine, differences (p < 0.01) in cholesterol synthesis rates between groups fed fish oil and beef tallow ad libitum were not observed with energy restriction. Energy restriction increased (p < 0.05) TG-FA synthesis rates in intestine of fish and safflower oil-fed groups, but not in that of olive oil- and beef tallow-fed animals.


CONCLUSIONS
These results demonstrate the possible importance of dietary fat selection to control against hyperlipidemia during consumption of weight-reduction diets.
Cha
M C
MC
School of Dietetics and Human Nutrition, McGill University, Montreal P.Q., Canada.
Jones
P J
PJ
D000818:Animals; D001835:Body Weight; D002784:Cholesterol / Q000096:biosynthesis* / Q000097:blood; D018752:Diet, Fat-Restricted; D004041:Dietary Fats / Q000008:administration & dosage* / Q000145:classification; D002149:Energy Intake / Q000502:physiology*; D005223:Fats / Q000008:administration & dosage; D005227:Fatty Acids / Q000096:biosynthesis* / Q000097:blood; D005395:Fish Oils / Q000008:administration & dosage; D007421:Intestine, Small / Q000737:chemistry / Q000378:metabolism; D008099:Liver / Q000737:chemistry / Q000378:metabolism; D008297:Male; D000069463:Olive Oil; D010938:Plant Oils / Q000008:administration & dosage; D051381:Rats; D017207:Rats, Sprague-Dawley; D012450:Safflower Oil / Q000008:administration & dosage; D014280:Triglycerides / Q000096:biosynthesis / Q000097:blood
D004041:Dietary Fats; D005223:Fats; D005227:Fatty Acids; D005395:Fish Oils; D000069463:Olive Oil; D010938:Plant Oils; D014280:Triglycerides; D012450:Safflower Oil; D002784:Cholesterol; C013698:tallow