Effect of Chain Length and Saturation of the Fatty Acids in Dietary Triglycerides on Lipid Metabolism in Wistar Rats

Dietary fatty acids are associated with lipid health. We investigated the effect of the chain length
and the degree of saturation of fatty acids in dietary triglycerides on serum lipid profiles and
hepatic lipid metabolism in Wistar rats. Fat component of the basal diet (soybean oil) was
replaced with fats with fatty acids of different chain lengths and saturation and the serum lipids
were monitored for 150 days. Principal component (PC) analysis of serum lipid components
were related to chain length and saturation using second order polynomial regression analysis.
The combined effect of chain length and saturation on PC 1 scores were evaluated by multiple
regression analysis. Variation of lipid parameters cannot be well-explained by chain length or
saturation alone. Consistent with the formation of large amounts of lipid droplets in the liver,
expression of sterol regulatory element binding protein -2 (SREBP2) and peroxisome
proliferator-activated receptors (PPARα) involved in hepatic lipid metabolism showed
significant (P<0.05) downregulation in margarine diet group and SREBP2 in dairy butter diet
group compared to the control group. Average chain length of fatty acids in triglycerides has a
higher influence on the quality of serum lipid parameters than the average degree of saturation of
fatty acids.