Dietary Mackerel Oil in Pigs: Effect on Plasma Lipids, Cardiac Sarcolemmal Phospholipids and Cardiovascular Parameters

The influence of substitution of eicosapentanoic acid to the diet has been investigated in juvenile domestic pigs (7–8 kg) fed either a mixture of 4.5% (wt/wt) mackerel oil and 4.5% (wt/wt) lard fat (n = 12, ML group) or a 9% (wt/wt) lard fat (n = 12, L group) diet for 16 wk. Plasma triglyceride and total cholesterol did not change in L, but had decreased in ML to 51 ± 8 and 81 ± 8% of the initial values, respectively, at the end of this period; the largest decreases already occurred during the first 8 wk. HDL cholesterol of both L and ML were not affected. After 16 wk, postprandial responses of plasma triglyceride, total cholesterol and glucose and insulin, determined at hourly intervals during the first 8 h postfeeding, did not show any differences for the two dietary groups. In spite of a marked replacement of n-6 fatty acids by n-3 fatty acids in cardiac sarcolemmal membranes in ML, there were no major differences in cardiovascular performance (myocardial contractility, pre- and afterload, cardiac output and myocardial work) between L and ML, when measured under baseline conditions and after the heart was stressed by atrial pacing (heart rate: 160 beats/min). In conclusion, feeding moderate amounts of mackerel oil [0.3 g 20:5 n-3/(kg body weight·d)] to pigs during 16 wk produces decreases of the plasma levels of total cholesterol and triglyceride, but does not affect plasma HDL cholesterol and routine cardiovascular parameters.