Influence of enzyme supplementation and heat processing of barley on digestive traits and productive performance of broilers.

We studied the influence of enzyme supplementation (ES) of the diet and heat processing (HP) of barley on digestive traits and productive performance of broilers from 1 to 42 d of age. There were 6 diets arranged factorially with 2 doses (0 and 500 ppm) of a fungal enzyme complex with beta-glucanase and xylanase activity and 3 HP of barley (raw, micronized, and expanded). In addition, a control diet based on raw corn without ES was also included from 1 to 21 d of age. Enzymes reduced intestinal viscosity (IV) at all ages (P < or = 0.001) and water intake at 21 d of age (P < or = 0.01) and increased DM of the ileal contents at 28 d (P < or = 0.001). Also, ES increased total tract apparent retention of nutrients and BW gain and feed conversion ratio from 1 to 42 d of age (P < or = 0.001). Heat processing of barley increased IV at 7 and at 28 d of age, and DM of ileal contents (P < or = 0.05) at 28 d of age. In addition, HP improved feed intake (P < or = 0.01) and BW gain (P < or = 0.001) from 1 to 7 d of age, but the effects disappeared after 21 d of age. From 1 to 7 d of age, chicks fed micronized barley had higher IV, gained less weight, and had poorer feed conversion ratio than chicks fed expanded barley (P < or = 0.05). It is concluded that barley with enzymes can substitute for all of the corn in diets fed to broilers from 1 to 21 d of age. Enzymes improved digestive traits, retention of nutrients, and broiler performance from 1 to 42 d of age, and HP of barley improved performance from 1 to 7 d of age. The effects of HP of barley on broiler performance were more evident with expansion than with micronization.