| 240of29-week-old Hessian laying hens were randomly divided into4groups,6replicates eachgroup,10hens each replicate. Effect of quercetin on eggshell quality in laying hens which fed bybasal diet supplemented with0%,0.02%,0.04%and0.06%quercetin were studied,. Theexperiment included two periods: the early period of experiment (29-37weeks) and the late periodof experiment (39-47weeks). The experimental period lasted8weeks for the1-week preliminarytrial period and the7-week formal trial period. In this study, the effects of quercetin on performanceand eggshell quality were investigated and the possibility of quercetin as functional feed additiveswas explored. It will provide a theoretical basis for applying quercetin in livestock production.1．Effect of quercetin on performance in laying hensCompared with control,0.04%quercetin significantly reduced feed-egg ratio (P<0.01); Nosignificant treatment effect was observed in average egg weight (P>0.05);0.02%quercetinsignificantly increased the average laying rate by4.99%during the early period of experiment(P<0.05); During the late period of experiment,0.04%quercetin significantly increased averagelaying rate by7.96%(P<0.01).2．Effect of quercetin on eggshell quality in laying hensCompared with control,0.04%quercetin significantly improved relative eggshell weightduring the early period of experiment (P<0.01); During the late period of experiment, eggshellstrength was significantly increased by0.06%quercetin (P<0.05);Eggshell thickness wassignificantly increased by0.02%,0.04%and0.06%quercetin (P<0.05，P<0.01，P<0.0,1); Relativeeggshell weight was significantly increased by0.04%and0.06%quercetin (P<0.05, P<0.01);0.02%and0.04%quercetin significantly decreased ratio of broken and soft eggs (P<0.01).3．Effect of quercetin on calcium and phosphorus content of eggshell in laying hensCompared with control, calcium content in eggshell was significantly increased by0.02%,0.04%and0.06%quercetin during the early period of experiment (P<0.05, P<0.05, P<0.01);During the late period of experiment, calcium content in eggshell was significantly increased by0.04%and0.06%quercetin (P<0.05, P<0.01)；P content in eggshell was significantly reduced by0.06%quercetin (P<0.05).4．Effect of quercetin on serum traits in laying hens Compared with control, serum calcium content was significantly increased by quercetin duringthe two periods (P<0.01); No significant effect was observed in serum phosphorus (P>0.05),alkaline phosphatase content was significantly improved by0.04%quercetin (P<0.01) during theearly period of experiment; During the late period of experiment, alkaline phosphatase content wassignificantly decreased by0.02%quercetin (P<0.01); Hydroxyproline content was significantlydecreased by0.04%and0.06%quercetin (P<0.05, P<0.01).To sum up, a certain dose of quercetin significantly increased average laying rate, reducedfeed-egg ratio (feed conversion efficiency), and improved performance in laying hens. Also,quercetin improved eggshell quality and reduced the percentage of broken and soft eggs viainfluencing calcium and phosphate deposition in eggshell, and serum calcium, phosphorus, alkalinephosphatase and hydroxyproline in laying hens. Additionally, the comparison of the early period ofexperiment (29-37week) and the late period of experiment (39-47week) showed that quercetinrelieved the influences of the increase of age on the decline of eggshell quality including drops ofshell thickness and eggshell relatively weight in laying hens. Performance during the late periodwas significantly higher than that in during the early period. Appropriate doses of quercetineffectively improved average laying rate and decreased feed-egg ratio when the overallperformance was declined in laying hens. It indicated that performance had a greater increase withage by appropriate doses of quercetin in laying hens.Our data suggests that the optimum level of supplementation for quercetin is0.04%in thebasal diet for improving performance and eggshell quality. |
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