The objective of this study was to determine the effects of various levels of dietary licorice extract on egg production, egg weight, specific gravity, feed conversion ratio, egg shell quality and egg yolk color. One hundred 20 8 laying hens (58 weeks age) were divided to 4 groups with 4 replicates (8 hens each) in a complete block randomized design. Data were analyzed using ANOVA and means were separated using Tukey’s HSD (P < 0.05). The experimental diets were supplemented with 0, 2, 4 or 6 g/kg of diets licorice extract. Daily egg production, weekly egg weight and feed consumption were recorded. Three eggs in each replicate were used to measured egg components each other week. Daily egg production in hens fed diet supplemented with 4 g/kg of licorice extract numerically increased (P = 0.06) when compared with the control diet in the entire experiment. Hens fed diet 4 g/kg licorice extract had significantly increased (P < 0.05) shell thickness compared with those fed diets supplemented with 6 g/kg (389 vs. 374 mm). Percentage of abdominal fat pad was significantly decreased (P < 0.05) in birds fed diet containing 6 g/kg licorice extract compared with control diet (0.83 vs. 1.49%). Performance parameters (feed consumption, feed conversion ratio), egg parameters (egg weight, dry shell weight, egg-specific gravity, percentage of wet albumen and wet yolk based on percentage of whole egg weight) and organ weights were not influenced (P > 0.05) by licorice supplementation. It seems that licorice extract at the level of 4 g/kg may have positive effects on egg production, shell quality and decreases abdominal fat pad at 6 g/kg level.

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