RESUMEN
In laying hens of the Cornish breed about 1,8 kg of body weight, which, beside being fed abundantly for 4 days, were given 1 g of cholesterol and 1 g of pork fat in a piece directly into the crop, attempts were made to determine the level of fat compounds in blood plasma, in the wall of the abdominal aorta, and egg cell yolk. The control group was kept in similar conditions, receiving a bare piece of food. Blood was taken on empty stomach from the heart on heparin. With the methods adopted the following were examined in the plasma: total cholesterol, triglycerides, total fat and beta-lipoproteins. After bleeding the birds, extracts from the aorta intima and media and maturing egg cell yolk balls were made by the method of Folch et al., and then they were analysed with thin-layer chromatography on silica gel (Kieselgel-Fertigplatten DC Merck). Following densimetric measurements, the results obtained were statistically analysed, tabled and plotted in chromatograms. In general, almost a double concentration increase in the total cholesterol and fat, triglycerides and beta-lipoproteins was observed in comparison with control group. In the aorta analysed chromatographically, the mean level of phospholipids, free fatty acids, triglycerides and ester cholesterol increased almost twice, and that of monoglycerides ten times. In egg cell yolk more than a double increase in the level of phospholipids, triple of monoglycerides and over triple of free cholesterol and fatty acids, over quadruple of triglycerides and over sevenfold of free cholesterol was observed. In this way it was found that in laying hens of the Cornish breed on intensive atherogenic diet a rapid and high increase in the concentration of the lipids studied occurred after 4 days, particularly in maturing egg cells, in which it exceeded many times the control values.