Effects Of Quercetin On Performance And Egg Quality In Laying Hens

In this study,240of39-week-old Hessian hens were randomly alloted to4treatments with sixreplicates pens and10hens per pen. Control was fed basal diets, treatments were fed basal dietssupplemented with0.02%,0.04%and0.06%quercetin. The effects of quercetin on laying rate, eggquality and blood traits associated with egg quality in laying hens at39-week-old wereinvestigated and the possibility of quercetin as functional feed additives was explored. The dataswill provide a theoretical basis for applying quercetin in livestock production. This study wassummarized by five parts as belows:1. Effect of quercetin on performance in laying hensCompared with control, laying rate were increased by4.97%and8.14%(P<0.05) andfeed-egg ratio were lowered (P<0.05) at0.02%and0.04%quercetin. No treatment effect wasobserved in egg weight, feed intake and broken shell or soft shell rate (P>0.05). However,increasing and decreasing were observed in egg weight and in daily feed intake (P=0.058).2. Effect of quercetin on egg quality in laying hensCompared with control, yolk color and eggshell thickness were significantly improved by3.17%,4.20%and6.12%at0.02%，0.04%and0.06%quercetin (P<0.05). Haugh unit wereenhanced by3.20%and4.46%and relative weight of eggshell were increased at0.04%and0.06%quercetin (P<0.05). Eggshell strength was heightened at0.06%quercetin (P<0.05). However, notreatment effect was observed in yolk weight/egg weight and egg shap index (P>0.05).3. Effect of quercetin on egg components in laying hensCompared with control, content of yolk phospholipids was significantly improved by3.57%,8.23%and8.73%at0.02%，0.04%and0.06%quercetin (P<0.05), respectively. Content of yolkprotein was enhanced at0.04%quercetin (P<0.05). Yolk cholesterol was lowered at0.06%quercetin (P<0.05). No treatment effect was observed in content of water in egg, crude protein inegg white and crude fat in yolk (P>0.05).4. Effect of quercetin on serum traits in laying hensCompared with control, no treatment effect was observed in serum cholesterol andphosphorus (P>0.05). Serum calcium and total protein were increased at0.04%and0.06%quercetin (P<0.05). Serum uric acid was lowered at0.04%quercetin (P<0.05) and serum urea nitrogen was decreased at0.06%quercetin (P<0.05).5. Effect of quercetin on serum hormones in laying hensCompared with control, triiodothyronine was increased by0.02%，0.04%and0.06%quercetin(P<0.05). Estradiol was increased at0.02%and0.04%quercetin (P<0.05). Progesterone wasincreased at0.02%quercetin (P<0.05), follicle-stimulating hormone, luteiinizing hormone andgrowth hormone were increased at0.04%quercetin (P<0.05). Insulin-like growth factors-1andthyroxine were increased at0.06%quercetin (P<0.05).In conclusion, data from the experiment indicated that quercetin improved performance andegg quality via regulating nutrient metabolism and hormones level in laying hens at39-47weeksof age. Our data suggests that the optimum level of supplementation for quercetin is0.04%in thebasal diet for increase in performance and egg quality.