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.
