Effect of enzyme supplementation to improve gut performance of broilers fed diets containing varying levels of wheat.

An experiment was conducted in order to evaluate the effect of enzyme supplementation (Roxazyme ® G) on gut performance of broilers fed diets containing varying levels of wheat. Six isonitrogenous and isocaloric diets containing 30, 40 and 50 % wheat with or without supplemental enzyme fed to one hundred and eighty day-old broiler chicks for four weeks. There was significant (P<0.05) difference in the foregut digesta viscosity of birds fed on different experimental rations with and without enzyme supplementation and for the interaction of wheat and enzyme. Carcass data was not affected with different levels of wheat with or without enzyme supplementation. Introduction Wheat is a common source of energy and an excellent ingredient for poultry, but its high dietary inclusion have resulted consistently poor chick performance (Friesen et al., 1992). The most probable hindrance, which restricts the inclusion of wheat at higher levels in poultry diets, seems to be its chemical nature. Wheat contains relatively high level of non-starch polysaccharides (NSPs) as structural carbohydrates in the endosperm cell walls for which poultry do not have required endogenous enzymes. These NSPs are polymeric carbohydrates which differ in composition and structure from starch (Morgan et al., 1995) and possess chemical cross linking among them therefore are not well digested by poultry (Adams and Pough, 1993 and Annison, 1993). A part of these NSPs is water-soluble which is notorious for forming a gel like viscous consistency in the intestinal tract (Ward, 1995) thus by reducing gut performance. Predominantly water soluble and viscous arabinoxylans, which belong to pentosan group, are assumed the factor responsible. These pentosans also greatly increase the water intake by the birds, which lead to unmanageable litter problems caused by wet and sticky droppings. This deteriorates the hygienic conditions and carcass quality (Dunn, 1996). On the other hand, ß-glucans adversely affect all nutrients, especially protein and starch, utilization and are known to give rise highly viscous conditions in the small intestine of the chicks (Hasselman and Aman, 1986). Research work has suggested that the negative effects of NSPs can be overcome by dietary modifications including supplementation of diets with suitable exogenous enzyme preparations (Creswell, 1994). Enzymes break down the NSPs, decreases intestinal viscosity and eventually improve the digestibility of nutrients by improving gut performance. The present study was, therefore, conducted in order to evaluate the effects of enzyme supplementation (Roxazyme ® G) on gut performance of broilers fed diets containing varying levels of wheat. Materials and Methods One hundred and eighty day old broiler chicks of mixed sex were randomly divided into six groups of 30 birds, which were subdivided into three experimental units of 10 chicks each. These were randomly assigned to one of the six experimental rations, which were isonitrogenous and isocaloric containing 30, 40 and 50 % wheat with or without supplemental enzyme (Roxazyme ® G). Feed and water were available ad libitun and the chicks had access to 24-hour light throughout the experimental period. Foregut digesta viscosity was determined during experiment by employing the principle of rotational viscometery (sensing the torque