Growth Improvement by a Fiber-Degrading Enzyme Supplement in the Chicken

To determine the effect of a fiber-degrading enzyme supplement, Novozym 343_??_, on performance of the chicken, three experiments were conducted with Single Comb White Leghorn male chicks (experiments 1 and 2) and White Cornish × White Rock broiler chickens (experiment 3) fed on high fiber, low-energy diets. In the first experiment, the enzyme was supplemented at graded concentrations from 0 to 0.75g/kg to determine an optimal supplemental level. With increasing the enzyme concentrations, neutral detergent fiber (NDF) digestibility increased linearly, whereas N balance and ME value reached maximal values around 0.5g/kg. In the second experiment, supplementing with the enzyme at 0.5g/kg significantly improved body weight gain, feed efficiency, deposition of carcass fat, protein and energy, NDF digestibility, and dietary ME and DE values. The digested NDF accounted for about two-thirds of the DE increase observed in the birds fed the enzyme. In the last experiment, effect of enzyme supplementation at 0.5g/kg on growth performance and tissue weights of the broiler chickens was investigated. Body weight gain, feed efficiency, and breast muscle weight of broiler birds were significantly increased by supplementing with the enzyme. It was concluded that the enzyme supplementation would benefit growth performance of the chicken through enhanced dietary DE and hence ME values which was primarily brought about by increased digestibility of NDF when dietary energy was a limiting factor for the growth.