Effects of diets supplemented with lard fat or mackerel oil on plasma lipoprotein lipid concentrations and lipoprotein lipase activities in domestic swine.

Levels of plasma lipoproteins and lipoprotein lipase activities in post-heparin serum were measured in 24-h fasted pigs which were fed a diet containing either 21 energy % mackerel oil or 21 energy % lard fat for 8 weeks. Lipoprotein fractionation was performed separately by density gradient ultracentrifugation and agarose gel chromatography. After 8 weeks levels of plasma triacylglycerol (-62%) and cholesterol (-55%) were lower in the mackerel oil than in the lard fat-fed animals. The triacylglycerol decline was exclusively due to the VLDL fraction, while cholesterol was reduced in all lipoprotein fractions (VLDL, IDL, LDL and HDL). Lipoprotein lipase activity in post-heparin serum, taken 6 h after a meal, was 31% decreased in mackerel oil-fed animals. The results support the hypothesis that regular intake of fish oil reduces VLDL secretion.