Lipid composition of lymph and blood plasma of the cow

Abstract

SUMMARY Samples of prefemoral, thoracic and intestinal duct lymph have been collected under acute conditions from three cows grazing pasture and the lipid composition compared with that of plasma. The concentration of lipids in peripheral lymph was 16–36% of that found in plasma; the fatty acid compositions of peripheral lymph lipids were similar to those of plasma. Of the fatty acids present in intestinal and thoracic lymph 86 and 76% were esterified as triglycerides, 10 and 13% as phospholipids and 3 and 5% as cholesterol esters, respectively. Saturated and mono-unsaturated fatty acids were preferentially esterified as triglycerides whereas di- and tri-unsaturated acids were associated more with phospholipids. The content of di- and tri-unsaturated fatty acids was greater in the triglycerides and phospholipids derived from the intestine than in those found in plasma. The di- and tri-unsaturated fatty acids in intestinal and thoracic lymph were transported mainly in the form of triglycerides (45–62%) and phospholipids (21–33%). Cholesterol esters were quantitatively of minor importance in the transport of these fatty acids in lymph. The intestine does not appear to play any major role in the formation of the high concentration of cholesterol ‘linolenate’ found in bovine plasma. The process of lipid digestion in the cow appears to be similar to that found in sheep.