Effects of Quercetin on Performance and Lipid Metabolism in Laying Hens

Quercetin has a variety of biological activities. However, its application as a feed additive in poultry production is limited. In this study, the effects of quercetin on performance and lipid metabolism in Hessian laying hens were investigated and the possibility of quercetin to decrease cholesterol in eggs and Low Density Lipoprotein cholesterol（LDL-cholesterol） in laying hens were explored. A total of 240 laying hens at 29-week-old were randomly assigned to four treatments, with six replicates of 10 birds per replicate. The treatments were fed with basal diet supplemented with 0, 0.2, 0.4 and 0.6 g · kg-1 quercetin for 8 weeks. Layer performance, lipid concentration in livers, yolks and serum were measured at the end of the experiment. The results showed that laying rate had a quadratic correlation with the level of quercetin（p=0.056） and was maximized by the supplement level of 0.2 g · kg-1 diet. When the level of dietary quercetin increased, feed-egg ratio decreased. Crude fat and the total cholesterol of livers decreased by supplementation of quercetin. The total cholesterols of yolks also decreased and had a quadratic correlation with the levels of quercetin（p=0.019）. Insulin increased by supplement of quercetin. In conclusion, quercetin improved the performance and reduced egg yolk cholesterol by affecting serum hormone levels.