Size of Lipoproteins in Intestinal Lymph of Sheep and Suckling Lambs

Abstract

The relative importance of chylomicrons (Sf> 400) and very low density lipoproteins (Sf 20-400) in transporting lipids in lymph was investigated in surgically prepared adult sheep and pre-ruminant lambs fed low fat diets or infused intraduodenally with corn oil. The concentration of triacylglycerol in the intestinal lymph of sheep and lambs was increased from 520 and 925 mg/1oo ml to 2326 and 2367 mg/loo ml respectively when corn oil was infused into the duodenum and the ratio of triacylglycerol to phospholipid changed from 3 ·7 and 5 . 5 to 9·5 and 9·7 respectively. The flow of lymph also increased. Electron microscopy and analytical and preparative ultracentrifugation showed that lymph lipoproteins from sheep and lambs fed low fat diets consisted mainly of lipoproteins 50 nm in diameter and that very low density lipoproteins (Sf 20-400) contributed up to 75 % of the Sf > 20 lipoproteins. There were no lipoproteins with diameters above 150 nm.