Abstract: Effect of quercetin on eggshell quality in laying hens was studied.240 of 29-week-old laying hens with similar weight and laying rate were randomly divided into 4 groups,6 replicates each group and 10 hens each replicate.The control group was fed the basal diet,the experimental 1 to 3 groups were fed the basal diet supplemented with 0.02%,0.04%,0.06% quercetin.The results showed that compared with the control group,the experimental 2 group significantly improved relative eggshell weight during the laying peak period (P<0.01).During the late laying period,the eggshell thickness of the experimental 1,2 and 3 groups significantly increased (P<0.05),relative eggshell weight of the experimental 2 and 3 groups significantly increased by 0.27% (P<0.05) and 0.48% (P<0.01),the experimental 1 and 2 groups significantly decreased rate of broken and soft eggs (P<0.01).In eggshell,calcium content of the experimental 1,2 and 3 groups significantly increased (P<0.05) during the laying peak period.Calcium content of the experimental 2 and 3 groups significantly increased (P<0.05) and the experimental 3 group significantly decreased phosphorus content (P<0.05) during the late laying period.Quercetin groups significantly increased serum calcium content during the laying peak period and the late laying period (P<0.01),serum alkaline phosphatase content of the experimental 2 group significantly increased during the laying peak period (P<0.01),serum alkaline phosphatase content of the experimental 1 group significantly decreased (P<0.01),serum hydroxyproline content of the experimental 2 and 3 groups significantly reduced during the late laying period (P<0.05). In conclusion,0.04% quercetin effectively improved eggshell quality of laying hens during the late laying period.

Key words: quercetin; laying hens; eggshell quality