THE RELATIONSHIP BETWEEN AGE AND EGG-PRODUCTION, EGG COMPONENTS AND LIPOPROTEIN, LIPIDS AND FATTY-ACIDS OF THE PLASMA AND EGGS OF LAYING HENS

The relationship was studied between the age of hens from 27 to 51 wee ks and production, size and components of their eggs, the lipid and fa tty acid content of the yolks and the lipid composition of very low de nsity lipoproteins (VLDL) and that of total plasma. Age of the hen was positively correlated with the production of extra large eggs and lin oleic acid contents of plasma VLDL, but was negatively correlated with egg yolk lipid and the production of large, medium and small eggs. Ex tra large eggs had a significantly lower adjusted yolk percentage and higher adjusted albumen percentage than those of medium and large size eggs. Egg size did not significantly affect lipid or fatty acid conce ntration of egg yolks. It was concluded that older hens laid larger eg gs, with a greater proportion of albumen, a higher concentration of th e polyunsaturated fatty acid, LA, but less saturated fatty acids and t otal lipid than eggs from younger hens.