The influence of crude cottonseed oil in the feed on the blood and egg yolk lipoproteins of laying hens

Abstract

Lipovitellin, very low density lipoproteins (VLDL), low density lipoproteins (LDL), high density lipoproteins (HDL), and proteins of d greater than 1.20 were isolated from blood plasma and egg yolks obtained from hens fed a normal diet or one containing 2.5% of crude cottonseed oil. The amounts and compositions of each fraction were determined. Hen blood plasma and egg yolk VLDL and LDL obtained from hens fed a normal diet contained similar levels of lipid, and the fatty acid compositions of those lipids were, for the most part, similar. The percentages of VLDL and LDL in total lipoproteins were similar for plasma and egg yolk obtained from hens fed the normal diet. Separation of VLDL from LDL was not clear-cut in eggs from hens fed the diet which contained crude cottonseed oil. Lipovitellin, as it is isolated from egg yolk, did not appear to be present in any appreciable amount in hen blood plasma. Hen plasma appeared to contain about 10% of a liproprotein d greater than 1.20, the lipid of which was similar in fatty acid composition to that of lipovitellin except for palmitic and oleic acids. Lipids of all the different lipoproteins isolated from plasma and egg yolks of hens fed diets which contained 2.5% of crude cottonseed oil contained more stearic acid and less palmitoleic and oleic acids than did those from normal hens. The increased content of stearic acid increased the density of the lipoproteins so that a larger proportion of the lipoproteins were in the LDL and a smaller proportion were in the VLDL than in lipoproteins from normal plasma and eggs.