Effects of supplementation of diets containing high levels of rice bran with microbial phytase on the performance of broiler chicken

Abstract

An experiment was conducted to determine whether the adverse effects o f high rice bran (RB) levels in broiler diets could be overcome by supplementing the diets with microbial phytase. Twenty days old broiler chicks (n=300) were randomly allocated into 12 deep litter cages. Four dietary treatments were randomly allocated into 12 cages in 2 * 2 factorial arrangements. Dietary treatments were two dietary non-phytate phosphorus (NPP) levels (2.5 and 3.5 g/kg) with or without 1000 FTU o f microbial phytase. All the diets had 40% RB. Experimental diets were fed for 19 days from day 21-39. Cage-wise feed intake and weekly weight gains were measured. On day 40, birds were weighed and killed. Six carcasses from each treatment were randomly selected, eviscerated and the weights o f the internal organs such as intestinal tract, pancreas, liver, gizzard and proventriculus were measured. In general growth performances were inferior. Dietary NPP levels or phytase supplementation did not significantly affect the growth performance indices such as weight on day 28, 35 and 40 and weight gains. The highest live weight on day 40 (2211 g) was reported when 3.5 NPP (which contained the standard nutrient „ requirements) diet was given without phytase. Feed intake was also not significantly affected by the dietary NPP levels and phytase supplementation. The feed intake values, particularly from day 35-40 were substantially low compared to standard values. Feed conversion ratio was also not affected by the treatment. Carcass parameters such as the weight o f the pancreas, liver, digestive tract and gizzard were also not affected by the dietary treatments. It was concluded that adverse effects o f high levels o f rice bran inclusions in broiler diets could not be mitigated by supplementing the diets with microbial phytase.