Effects of Barley Cultivar and Dietary Supplemental enzyme on Performance, Egg Quality Traits, and Selected Blood Parameters of Laying Hens

The effect of supplementing two commercial multienzyme to diets included two barley cultivars (Sararood [71.99%] and Valfajr [66.39%]) on performance, egg quality, and blood parameters of laying hens was investigated in an 8-wk (65 to 73 wk of age) experiment.  The commercial multienzymes were Grindazym™ (with mainly β-glucanase and xylanase activity) and Hemicell® (with mainly β-mannanase activity). Each dietary treatment consisted of five replicates of six hens. Barley cultivar had no significant effect on the measured criteria  and there was no interaction between barley cultivar and enzyme throughout the study. Diet supplementation with enzymes reduced feed intake (P < 0.05). Hens receiving Grindazym-supplemented diets produced more eggs than those receiving diets without enzyme or supplemented with Hemicell (P < 0.05). Conversely, egg weight was higher for hens receiving the Hemicell-supplemented diets than for those fed the other diets (P < 0.05). Hens receiving the Grindazym-supplemented diet showed higher egg mass than those fed the unsupplemented diets (P < 0.05) and egg mass of hens receiving the Hemicell-supplemented diets was intermediate between these two groups. Feed conversion ratio was improved by enzyme supplementation throughout the study (P < 0.05). Serum concentration of triiodothyronine was higher in hens receiving the Grindazym-supplemented diets than that in hens receiving the diets with no enzyme or supplemented with Hemicell (P < 0.05). Overall, the nutritive value of barley could be improved by enzyme supplementation. However, the two enzyme sources had different effects on performance of laying hens probably due to different mechanisms of action.