To study effects of enzyme supplementation of guar meal (GM)-included diets on productive performance of laying hens, a total number of 144 Lohmann LSL-Lite hens were divided in 24 cages (n = 6) and a 3 × 2 factorial arrangement of treatments was employed. Six iso-caloric and iso-nitrogenous diets including three levels of guar meal (0.0, 25.0 and 50.0 g kg1) with and without enzyme (Hemicell®, 0.0 and 0.4 g kg1) were assigned to hens in 4 cages (replicates). Dietary GM inclusion significantly affected egg production (EP) on weeks 1, 4 and 6 as well as the overall trail period. Dietary treatments did not affect FI in the present experiment. Egg mass (g egg hen1 day1) in hens fed GM-included diet decreased during weeks 4-5 of trial. Including GM to diet of laying hens affected FCR during weeks 1, 4, 6 as well as the overall trial period (weeks 1-6). Hens fed diet with 5.0 g GM/100g showed increased FCR compared with the birds fed the control and those fed the diet with 2.5 g GM/ 100g diet during the trial. Enzyme supplementation did not affect FCR. Based on the results of this investigation it can be concluded that adding 5% GM to laying hens' diet has adverse effects on their productive performance and it seems that hens can tolerate GM in the diet up to 2.5% with no detrimental effects on EP, EM and feed efficiency.
