Nutritional effects of enzymatically modified soybean oil with caprylic acid versus physical mixture analogue in obese Zucker rats

Enzymatically modified soybean oil with caprylic acid (SL), a physical mixt ure of tricaprylin and soybean oil (PHY), and soybean oil as control were f ed (20% of diet weight) to female obese Zucker rats. Both lipids (SL and PH Y) have similar total fatty acid composition containing 23.4 mol % caprylic acid (C8:0) but have different lipid structures. After 21 days of feeding, the bodyweight gain was 36.4% in the SL-fed group and 35.2% in the PHY-fed group, respectively; whereas the body weight of the control group increase d 41.6%. Significant differences in the respiratory exchange ratio were obs erved between the SL and PRY groups. However, the contents of glucose, tota l and high density lipoprotein (HDL) cholesterol, and very low density and low density lipoprotein (VLDL + LDL) cholesterol in serum were not signific antly different between the SL- and PHY-fed groups or among the three dieta ry groups (control, SL, and PHY) (p < 0.05). On the other hand, plasma tota l cholesterol and plasma triacylglycerol (TAG) were significantly higher in SL- and PHY-fed groups than in the control group. In the liver and inguina l adipocyte TAG, C8:0 was found in the SL-fed group, whereas it was not obs erved in the liver and inguinal adipocyte TAG of the PHY-fed group, which s uggests that positional distribution of C8:0 of the TAC molecule is an impo rtant consideration in the metabolism of lipids. This study showed that dif ferent positional distribution in TAG molecules lead to different metabolic fates, resulting in the change of fatty acid composition in liver and ingu inal adipose TAG in female Zucker rats.