The effect of drying temperature and exogenous enzyme supplementation on nutrient digestibility, nitrogen retention and AME of maize/soy-based diets for broiler chickens

摘要

The usefulness of exogenous enzymes to improve the nutritional value of diets that are based on wheat and barley has been well described in the literature. However, there is a paucity of information on the effect of exogenous carbohydrases on the nutritional value of maize-based diets for poultry (Cowieson, 2005). Many factors influence the nutritional value of maize, including post-harvest processes and climatic conditions during growth. When maize is harvested with a high moisture content and thendried aggressively the nutritional value may be compromised, with a concomitant effect on dietary apparent metabolisable energy (AME), body weight gain (BWG) and feed conversion ratio (FCR). These inimical effects are associated with denaturation of heatlabile vitamins, damage to protein via an interaction with reducing sugars and retrograde starch formation after heat processing (Iji et al., 2003; Cowieson, 2005). Further, the dramatic increase in feed ingredient pricing in recent years has been an impetus for continued research in energy and protein metabolism.