Improved nutrient utilization and growth performance of broiler chickens fed diets supplemented with multicarbohydrase enzyme preparations

Among the feedstuffs commonly used in Canadian poultry diets, wheat, soybean meal (SBM), canola meal (CM), and peas contain significant amounts of nonstarch polysaccharides (NSP) which can be degraded by carbohydrases supplementation. Low intestinal viscosity (2.0-5.0 mPa s) has been reported for broilers fed Canadian wheat-based diets. Supplementation of wheat-based diets with a single xylanase activity has often led to minor improvements in growth performance. In attempts to target the NSP in SBM, CM, and peas with carbohydrase enzymes, little response has been observed. Full-fat canola and flax seeds are valuable sources of energy, protein and alpha-linolenic acid for poultry diets. However, the energy utilization from these seeds is limited due to the oil encapsulating effect of the cell wall NSP. The objectives of the current research were (1) to screen various carbohydrase enzyme preparations in vitro for their ability to depolymerize the NSP of wheat, SBM, CM, peas, and flaxseed meal; and (2) to evaluate the effectiveness of selected enzyme combinations in improving nutrient utilization from wheat, SBM, CM, peas and full-fat canola and flax seeds when fed to broiler chickens. The in vitro studies demonstrated that a more pronounced degradation of NSP could be achieved when the enzyme preparations were used in concert. The selected enzyme combinations were evaluated further in a 2-wk growth performance and nutrient digestibility trial with broiler chickens fed a practical diet based on wheat, SBM, CM, and peas. All enzyme combinations were effective in improving (P < 0.05) growth performance, dietary AMEn, and starch and protein digestibilities of the birds with an intestinal viscosity being reduced from 3.3 to 2.3 mPa s. A combination of 4 carbohydrases was found to be superior (P < 0.05) to others in improving ileal protein digestibility and feed-to-gain ratio which were not due to a further reduction in digesta viscosity. When this enzyme combination was supplemented to 3 corn-based diets each containing 30% of either SBM, CM or peas, an improvement (P < 0.05) in NSP and protein digestibilities and dietary AMEn content was observed only for the SBM-containing diet. The performance of birds fed the 3 diets was not affected by the enzyme addition. The same enzyme blend was further used in a factorial experiment to evaluate if there is an interaction between fat type [beef tallow or canola oil (50 g/kg diet)] and carbohydrase addition [none or carbohydrases (0.4 g/kg diet)] in practical wheat-based broiler diets. (Abstract shortened by UMI.)...