A DIET CONTAINING MYRISTOLEIC PLUS PALMITOLEIC ACIDS ELEVATES PLASMA-CHOLESTEROL IN YOUNG GROWING SWINE

The objective of this study was to test the effect of a novel fatty ac id mixture, enriched with myristoleic and palmitoleic acids, on plasma lipoprotein cholesterol concentrations. Weanling pigs were assigned t o one of six groups and each group received a diet differing in fatty acid composition. Diets were fed for 35 days and contained 10 g added cornstarch/100 g (to provide baseline data) or 19 g added fatty acids/ 100 g. For those diets containing added fatty acids, extracted lipids contained 36% myristoleic plus palmitoleic acid combined (14:1/16:1 di et), 52% palmitic acid (16:0 diet), 51% stearic acid (18:0 diet), 47% oleic acid (18:1 diet), or 38% linoleic acid (18:2 diet). With the exc eption of the cornstarch diet, all diets contained approximately 30% m yristic acid. There were no significant differences in weight gain acr oss treatment groups (P = 0.22). All diets caused a significant increa se in triglycerides and in total, low density lipoprotein, high densit y lipoprotein, and very low density lipoprotein cholesterol. The incre ase in total plasma cholesterol from pretreatment values was greatest in pigs fed the 14:1/16:1 and 18:1 diets. However, the increase in low density lipoprotein cholesterol from the pretreatment concentration w as greatest in the 14:1/16:1-fed pigs. Increases in very low density l ipoprotein cholesterol above pretreatment concentrations were lowest i n 16:0-fed pigs and greatest in 18:l-fed pigs. Dietary fatty acids eli cited changes in plasma fatty acids which generally were reflective of the diets, although the 18:0 diet did not alter plasma fatty acid con centrations and the 16:0 diet increased plasma 16:0 only at the end of the study. These results demonstrated that the combination of myristo leic plus palmitoleic acids increased plasma cholesterol in young pigs , suggesting that fatty acid chain length, rather than degree of unsat uration, is primarily responsible for the effects of fatty acids on ci rculating lipoprotein cholesterol concentrations.