Effect of Feeding Cholesterol to Laying Hens and Chicks on Cholesterol Metabolism in Pre- and Posthatch Chicks

Single Comb White Leghorn laying hens that were 60 wk of age were fed wheat and soybean meal diets containing either 0 or 1% cholesterol. Birds were artificially inseminated, and fertilized eggs were collected for incubation after a plateau of egg cholesterol content was reached. Posthatch chicks were raised with starter diets containing either 0 or .5% cholesterol. Samples of developing embryos and posthatch chicks at various stages were prepared for cholesterol analysis. As compared with controls, cholesterol content of eggs from hens fed 1.0% cholesterol diet was increased by approximately 70%. Embryos from the cholesterol-loaded eggs had significantly higher (P less than .05) cholesterol content. The plasma total cholesterol (TC) level in chicks from cholesterol-loaded eggs, when compared with TC in control eggs, was significantly higher at hatching but decreased to the same level by 2 wk after hatching. Cholesterol feeding to newly hatched chicks elevated plasma TC and high-density lipoprotein cholesterol levels. The TC contents of liver and heart, but not skeletal muscle, were significantly higher in chicks fed the .5% cholesterol starter diet than those fed the cholesterol-free diet. These results show that cholesterol metabolism in developing embryos and posthatch chicks is influenced by cholesterol in both maternal and chick diets.