Galactanases and Mannanases Improve the Nutritive Value of Maize and Soybean Meal Based Diets for Broiler Chicks

Abstract

Maize and soybean meal are the most common ingredients in diets for monogastric animals. Although maize is low in anti-nutritive factors, soybean meal often contains significant levels of soluble galactans, mannans or oligosaccharides of the raffinose series that may cause considerable nutritional disorders when ingested. It is well established that cellulases and xylanases are very effective in improving the nutritive value of barley, wheat or rye based diets for broiler chicks through the hydrolysis of soluble glucans and arabinoxylans. A study was undertaken to identify the most important exogenous enzymatic activities for decreasing the detrimental effects associated with the ingestion of soybean meal soluble polysaccharides. The data showed that birds fed on a mash maize-soybean meal based diet supplemented with the enzyme mixture Ronozyme® VP displayed improved final body weight, when compared with birds receiving the enzyme preparations Roxazyme® G200 or Alpha-Gal® 1000 (P=0.08). In vitro enzyme assays suggested that the positive effect associated with the intake of Ronozyme® VP is correlated with the presence of galactanase and mannanase activities. Zymogram analysis demonstrated that the molecular integrity and activity of the exogenous galactanases and mannanases remains relatively unchanged in the crop and the duodenal contents. Together the data suggest that hydrolysis of mannans and galactans by exogenous enzymes in maize-soybean meal based diets, result in an improvement of broiler performance.