Effect of Phytase and Glucanase on the Ileal Digestible Energy of Corn and Soybean Meal Fed to Broilers

The current research was designed to determine the effect of phytase and glucanase on the energy value of corn and soybean meal (SBM) separately for broilers at various ages. The treatments were arranged as a 2 x 2 x 2 factorial, with 0 or 500 phytase units/kg or with 0 or 500 units of glucanase/kg, supplemented to either corn or SBM, with each combination represented by 6 cages of 10 birds. Diets of pure corn and soybean meal were not supplemented with additional nutrients, and were fed for 3-d periods beginning at 7, 14, or 21 d of age, representing the immature, transitional, and mature digestive tract, respectively. Each experiment was performed on a different group of birds from the same hatch. At the end of each experimental period, the broilers were euthanized and the contents of the ileum, duodenum and jejunum (pooled), and pancreas were removed for analysis. The ileal samples were analyzed for acid-insoluble ash and gross energy to determine the ileal-digestible energy (IDE) of the feedstuffs. The pancreas and duodenal-jejunal samples were analyzed for proteolytic and amylase activity to determine the influence of practical levels of phytate on enzyme activity. Results showed that neither phytase nor glucanase influenced enzyme activity in the digesta or pancreas, suggesting that practical levels of phytate did not influence the activity of proteolytic enzymes or amylase. Phytase did not influence the IDE value of either corn or SBM, and improved DM digestibility of the feed only for corn fed at 21 to 23 d. Glucanase improved IDE in both the corn and SBM diets at all ages, and improved DM digestibility in corn diets at all ages and SBM diets fed at 14 to 16 d. The IDE and DM digestibility of corn and the digesta and pancreatic enzyme activities increased with age, whereas the IDE of SBM was similar among age groups. The relative effect of glucanase on IDE of both feedstuffs was similar among age groups.