Characterization of chick serum lipoproteins isolated by density gradient ultracentrifugation

Abstract

Serum lipoproteins from 12h fasted male chicks (15-day-old) were separated into 20 fractions by isopycnic density gradient ultracentrifugation. A new procedure was described by collecting the different fractions from the bottom of tube instead of by aspiration from the meniscus of each tube. Analyses of chemical composition of serum lipoproteins have permited to reevaluate the density limits of major classes : VHDL, d> 1.132 g/ml; HDL, d 1.132–1.084 g/ml; LDL, d 1.084–1.038; IDL, d 1.038–1.022; and VLDL d≶1.022. HDL fractions clearly predominated (approx. 77% of total lipoproteins) while IDL and VLDL were present at low percentage. LDL was the fraction richest in cholesterol; triacylglycerol content clearly increased from HDL to VLDL, while protein content decreased. All the chemical components of chick serum lipoproteins were accumulated in HDL, although triacylglycerol was relatively distributed in all the lipoprotein classes.