the experiment was carried out to verify if total cholesterol, hdl-cholesterol and triacylglicerol plasma levels are affected when laying hens are fed rations containing different dietary oil sources. one hundred sixty 50 week-old hens, assigned to four treatments with five replicates using 8 hens per replicate were used. the experimental period was of 84 days divided in 3 cycles of 28 days each. in the last day of each cycle, blood samples of 2 hens per replicate were randomly choose and blood samples were collected. on the other hand, blood was also collected at 7 am, 11 am and 3 pm aiming to study the daily changes of these lipids. blood lipid parameters were not affected by different dietary oil sources (p > 0.05); however, hdl-cholesterol did change during the day, giving evidence that this lipid is indeed involved in the egg yolk formation.