Abstract: 【Objective】 The purpose of this experiment was to investigate the effect of dietary quercetin on prolonging storage time of eggs.【Method】 A total of 270 healthy, 380-day-old Yukou Jingfen No.8 laying hens with similar body weight and laying rate were randomly divided into 5 groups with 6 replicates per group and 9 hens per replicate.The blank control group was fed with corn-soybean meal basal diet, the positive control group was fed the basal diet with 200 mg/kg vitamin E.The three experimental groups were supplemented with 0.03%, 0.06% and 0.09% quercetin in the basal diet, respectively.The experiment lasted for 70 d.In the end of the experiment, eggs were collected and stored in 4 ℃ for 0, 7, 14 and 28 d.The egg quality, content of MDA, lipids and fatty acids and bacterial colony of eggs were analyzed at different storage times.【Result】 Compared with the blank control group, on day 0 after storage, the thick albumen content and albumen pH of eggs in positive control and quercetin groups were significantly increased (P<0.05), the phospholipid content of egg yolk in 0.09% quercetin group was significantly increased (P<0.05), the palmitic acid content of egg yolk in 0.03% quercetin group was significantly increased (P<0.05), and the arachidonic acid methyl ester content was significantly decreased (P<0.05).On day 14th of storage, the triglyceride content of egg yolk in 0.09% quercetin group was significantly decreased (P<0.05).On day 28th of storage, the alpha linolenic methyl ester content of egg yolk in 0.06% quercetin group was significantly decreased (P<0.05), and the content of gamma linoleate methyl ester and arachidonic acid methyl ester of egg yolk in 0.09% quercetin group was significantly decreased (P<0.05).Compared with the positive control group, the phospholipid content of egg yolk in 0.03% and 0.09% quercetin groups was significantly increased on day 0 after storage (P<0.05).On day 7th of storage, the phospholipid content of egg yolk in quercetin group was significantly increased (P<0.05).On day 28 of storage, the triglyceride content of egg yolk in quercetin group at was significantly decreased (P<0.05).In blank control group, the total number of colonies detected on the surface of eggshell stored for 28 days was 2.4×10³ CFU/g, while no bacterial colonies were detected in eggshell, albumen and yolk in other gropus.【Conclusion】 Dietary quercetin could improve egg quality, increase the contents of phospholipid, saturated fatty acids and antibacterial ability, so as to prolong the storage time of eggs.The results of this study provided a reference for the application of quercetin feed additive in prolonging the storage time of eggs.

Key words: quercetin; storage time; egg quality; antibacterial ability; colonies number