An experiment was conducted to evaluate guar meal (GM) as a source of protein on laying (58 weeks of age) performance and egg quality. Two hundred 20 8 laying hens (58 weeks of age) were fed diets containing 100 J. Anim. Sci. Vol. 88, E-Suppl. 2/J. Dairy Sci. Vol. 93, E-Suppl. 1/Poult. Sci. Vol. 89, E-Suppl. 1 0, 3, 6 and 9% guar meal with/without β-mannanase (Hemicell) for 12 weeks. A complete block randomized design with 4 × 2 factorial arrangement were used to have 8 diets of each fed to 4 replicate hens of 9 each. Daily egg production and weekly egg weight and feed consumption were recorded. Three eggs from each replicate were used to measured egg components each other week. Hen-day egg production was significantly decreased when hens fed diets contained 6 and 9% GM in first week and only 9% GM at second week of experiment as compared with 0 and 3% GM fed birds. Whereas hen-day egg production was not influenced when hens fed up to 9% GM after third week. Egg mass was significantly lower when hens fed 9% GM during the experimental periods compared with control and 3% GM fed birds (46.8 vs. 50.8 or 52.4, respectively). Feed conversion ratio (FCR) in 3 initial weeks of experiment was significantly higher in 9% GM fed birds. Feeding of GM did not affect specific gravity, percentage wet albumen and wet yolk based on percentage of whole egg weight and shell weight and thickness. Feed consumption, hen-day egg production, egg mass, FCR and egg quality were not affected by Supplementation of β-mannanase during the experimental periods. The results of this study showed that 6% GM may be added to the diet of laying hens with no adverse effects on performance.

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