The objective of present study was to determine the effects of β-mannanasebased enzyme (Hemicell®) on productive performance and egg quality in diets containing graded levels of Whole date waste (WDW) fed to laying hens. A total of 336 Hy-line leghorn hens after production peak were randomly divided into 56 cages. Eight iso-energetic and iso-nitrogenous experimental diets in a 4 × 2 factorial arrangement including four levels of WDW (0, 10, 20 and 30%) and 2 concentrations of supplemental β-mannanase (0 or 0.06 %) were prepared. Each dietary treatment was fed to 7 cages (6 birds/cage) from 32 to 38 wk of age. During the experiment, daily egg production, egg weight and feed intake were measured. At the 6th wk, egg quality traits were also recorded. The results showed that there was no interaction between WDW inclusion and enzyme supplementation on performance and egg traits. Dietary supplementation of WDW more than 10% significantly decreased egg production and egg mass compared to no WDW recipient hens (control diet) during the entire experiment (P<0.05). Inclusion of 30% WDW to the diet, significantly increased overall feed conversion ratio compared to the control group (P<0.05). The treatment with 20 and 30% WDW also resulted in lower eggshell thickness as compared to 10% WDW (P<0.05). The dietary inclusion of 10% WDW also increased yolk index as compared to the control and 30% WDW groups (P<0.05). Enzyme supplementation had no significant effect on productive performance as well as egg quality characteristics. Based on the results of this experiment, it can be concluded that WDW could be included to laying hens diets up to 10% with no deleterious effects on performance and egg quality characteristics.
