Influence of Enzyme Supplementation on the Bioavailable Energy of Barley

The influence of enzyme supplementation on the bioavailable energy of barley and apparent protein digestibility (APD) of barley-based diets was examined in four experiments. Wheat was replaced by Scout barley (hull-less) at 25% increments to a maximum of 75% of the diet The available energy for young chicks (AMEn) significantly increased due to enzyme supplementation as the barley component of the diet increased. No significant increase was observed when the same diets were fed to adult roosters (TMEn), which may be attributed to the age of the birds. The enzyme addition had a differential effect on the AMEn, values of four different barley cultivars. The greatest increase in energy was noted with Scout (25.3%); no increase was observed with Bedford (hulled) barley. When Scout barley was supplemented with either corn oil or tallow, the AMEn and ADP values of the diets increased due to enzyme supplementation, irrespective of the fat source. These results suggest that the bioavailable energy of unsupplemented barley depends on the cultivar and its viscosity as well as on the β-glucan content The age of the assay bird is important when assigning an energy value for barley containing antinutritive factors such as β-glucans. Currently, derived AMEn values for barley allow for a better prediction of performance parameters for young broilers.