Studies on the effect of feeding cupric sulfate pentahydrate to laying hens on egg cholesterol content

Two experiments were conducted to test the hypothesis that pharmacological levels of dietary Cu could reduce egg cholesterol content. White Leghorn hens 30 to 39 wk of age were fed corn and soybean meal diets with 0, 125, or 250 mg supplemental Cu/kg diet from cupric sulfate pentahydrate (basal diet = 6.74 mg Cu/kg). Body weight, feed consumption, egg weights, egg specific gravity, and Haugh Units were not consistently affected during the 8-wk feeding trials. Egg production was significantly increased (P < 0.05) in the second 4-wk period by supplemental Cu in both experiments. Egg yolk cholesterol concentrations were decreased by feeding 125 mg Cu/kg diet (11.7 vs 8.6 mg/g, average of two experiments); feeding 250 mg Cu/kg resulted in further declines in egg cholesterol but the differences were not significant (7.9 mg/g). Changes in plasma cholesterol concentrations were similar to those of yolk cholesterol. Small but significant amounts of Cu accumulated in the yolks and shells of eggs from Cu-supplemented hens; however, most of the Cu fed was found in the excreta.