Exogenous carbohydrase in corn-soy diets for broilers

Published literature on the effect of carbohydrase enzymes (CE) on energy availability, nutrient digestibilities and growth performance of broilers fed corn-soybean meal-based diets is reviewed. Data from experiments involving CE preparations displaying single- to multiple-activities has shown improved metabolisable energy by 3% and digestibility of protein by 5%. Despite the observed variation in absolute values for individual amino acids, the improvement in amino acid digestibility appeared to be 27% of the undigested fraction. The positive effect on nutritive value are consistent with the improvements in body weight gain (0.8 to 10.4%; mean = 4.3%) and feed efficiency (1.3 to 9.3%; mean = 3.7%). Possible mechanisms contributing to these effects and the factors thought to explain the variability in responses has been discussed.