Metabolism & Nutrition VI

A completely randomized design experiment was conducted to evaluate the effect of feeding different levels (0, 2.5, 5.0, 10.0, 20.0%) of guar meal (GM) in laying hen diets over a 8-wk trial period. A total of 180 Hisex laying hens (25wk old) of similar body weight were randomly distributed among 5 treatments with 6 replicates with 6 hens each. Body weight, body weight gain, egg produced per hen, feed consumption, feed conversion ratio, egg weight, egg mass per hen, and Haugh units, yolk color, and egg specific gravity were measured. Body weight and body weight gain for hens fed 10 and 20% GM were significantly lower than hens fed 0, 2.5, or 5% GM. Hens fed 10% GM supported a sig­ nificantly higher egg number and percentage of egg produced per hen than the control. Egg number and percentage of egg produced per hen were significantly lower for hens fed 20% GM than hens fed 0, 2.5,5, or 10% GM. Hens fed 20% GM consumed significantly lower feed than those fed 0, 2.5,5, or 10% GM. A significant feed conversion ratio in­ crease was existed for the 20% GM group compared to the remaining treatments. Egg weight decreased significantly for hens fed 20% GM compared to the other treatments. Egg mass for hens fed 5 and 10% GM was significantly higher than the control. However, hens fed 20% GM showed significantly the lowest total egg mass per hen. Egg yolk of hens received 5% GM were similar to the hens fed 10% GM, whereas hens fed 5% and 10% GM produced eggs with higher yellowness val­ ues than the control group. Egg specific gravity increased significantly for hens fed 20% GM compared to the other treatments. Mortality rate was significantly higher for the control group than hens fed 2.5 and 10% GM. Results showed that GM can be fed to laying hens at a level up to 10% without adverse effects on laying hen performance.