Dietary mackerel oil in pigs: effect on plasma lipids, cardiac sarcolemmal phospholipids and cardiovascular...

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.