Use of palmitoleate and myristoleate to establish the effects of fatty acid chain length and saturation on plasma cholesterol

Abstract

Specific objectives of this study were to test the hypothesis that fatty acid chain length, rather than saturation, is primarily responsible for the effects on plasma lipoproteins. Weanling pigs were assigned to six groups and each group received a diet differing in the main fatty acid. Diets were fed for 35 days and contained 0 (control group) or 10% added fat (by wet weight). The dietary fats contained approximately 40% myristoleate and palmitoleate combined (14:1/16:1 diet), 55% palmitate (16:0), 55% stearate (18:0), 55% oleate (18:1), or 40% linoleate (18:2). All diets contained 35% myristate. Blood samples were obtained at one week post weaning prior to the feeding trial and then at weeks 1, 3, and 5 of the feeding trial. Total cholesterol and triglycerides were quantitated with Sigma Diagnostics reagents, and lipoprotein cholesterol concentration was measured with the Quantimetrix LipoPhor System. Fatty acid composition of the plasma, longissimus tissue, and adipose tissue was analyzed by gas-liquid chromatography. There were no significant differences in weight gain throughout the study. Total cholesterol increased from approximately 80 mg/100 mL (pretreatment) to 138 (control), 152 (18:0), 157 (16:0), 194 (18:2), 209 (14:1/16;1) and 209 (18:1) mg/100 mL by 21 days on the test diets. Triglycerides increased from an average of 32 mg/100 mL (baseline) to 66 mg/100 mL (day 21) (no differences among treatment groups). The average amounts of LDL and HDL cholesterol increased from 33 and 37 mg/100 mL (baseline) to 69 and 90 mg/100 mL (day 21), respectively. Differences in plasma and tissue fatty acid composition were reflective of the diets. Plasma myristate was elevated at weeks 1 and S in all groups except for the control group. The monounsaturated fatty acid mixture resulted in increased plasma myristoleate and palmitoleate. Also, plasma linoleate was elevated in the group fed the high-linoleate diet. In both lean and adipose tissues, myristoleate was greater in the group fed the monounsaturated fatty acid mixture...