Search

Developmental changes in the lipid transport system in two lines of broilers, selected for high or low adiposity, have been investigated during the first 7 weeks after hatching. The major lipoprotein classes in the plasma of lean and fat chickens 2, 3, 4, 5 and 7 weeks old were isolated by density gradient ultracentrifugation. The 2-week old chickens presented an heterogeneous distribution of high-density lipoproteins (HDL), often appearing as two distinct gradient bands; their very-low-density lipoproteins (VLDL) were rich in cholesterol (25-30%) and relatively poor in triglycerides (approximately 35%). As the birds grew older, the HDL subclass of lower density disappeared, tending to fuse with that of higher density; at the same time, the triglyceride content of VLDL and HDL levels increased progressively in the two lines, their concentration being significantly higher in the fat line. These developmental changes suggest that our two lines of chickens are a suitable model for studies of the onset and hormonal control of the specific fattening process during growth.