Whole body nutrient accretion, growth performance and total tract nutrient retention responses of broilers to supplementation of xylanase and phytase individually or in combination in wheat-soybean meal based diets

Growth performance, total tract nutrient retention and whole body nutrient accretion rates responses of broilers to supplementation of enzymes containing phytase or xylanase activities were investigated using 300 broilers. At day old, 280 broilers were assigned to 5 dietary treatments which were: 1) positive control (PC) diet which met NRC (1994) nutrient requirement for broilers, 2) negative control (NC) diet which was marginally deficient in phosphorus and ME, 3) NC plus phytase added at 1,000 FTU/kg, 4) NC plus xylanase added at 4,000 U/kg and, 5) NC plus phytase and xylanase added at 1,000 and 4,000 units/kg, respectively. Each treatment had 8 replicate cages with 7 birds per replicate cage. Comparative slaughter technique was used for determination of whole-body nutrient accretion rate. Twenty broilers with the same initial body weight as the 280 broiler chicks used in the growth trial made up the initial slaughter group killed at day 0. A final slaughter group of 40 birds, one bird from each cage, were slaughtered on day 21. The birds selected were those with body weight closest to the average body weight of the birds in each replicate cage. Phytase alone or combined with xylanase improved weight gain and bone ash (P < 0.05). Phytase alone improved (P < 0. 5) total tract P retention and ME, phytase and xylanase combined improved (P < 0.01) total tract dry matter and ME. Phytase alone improved (P < 0.5) whole body daily accretion rates of dry matter, protein, fat, P, and Ca in comparison to NC treatment. Overall, phytase in wheat-based diet improved growth performance and whole body accretion of minerals and protein, the improvement in protein accretion is an indication of improvement in nutrient utilization resulting from phytase use.