ENERGY DIGESTIBILITY IN BROILER CHICKENS FED COTTONSEED MEAL BASED-DIETS SUPPLEMENTED WITH EXOGENOUS PHYTASE

Abstract

A total of 2881-day-old Arbor acres broiler chicks (BC) fed broiler starter for 20 days were used to investigate the effect of phytase on the digestibility of energy. On day 21, the chicks were weighed and allotted to 6 treatments with 6 replicates of 8 birds each using a 3x2 factorial arrangement in a randomized complete block design. Between days 25 and 27 post-hatch, samples of fresh excreta were collected once daily bulked and stored at -4ºC. On day 28, the birds were euthanized with carbon (IV) oxide asphyxiation and dissected to obtain digesta from the distal two-third of the ileum. Six semipurified diets with 150, 300 and 450g/kg rice husk (RH) and 0 or 1000 units of phytase were formulated. Ileal and excreta energy of the birds was significantly (P<0.05) reduced by feeding graded levels of cottonseed meal (CSM), while interaction of phytase and energy had no significant (P>0.05) effect on the ileal energy (IE) but significantly reduced (P< 0.05) excreta energy (EE). Apparent energy digestibility (AED) increased (P<0.05) by feeding graded levels of CSM while retained energy digestibility (RED) also increased (P<0.05) with the interaction of phytase and CSM. Increasing dietary concentration of energy intake from CSM, addition of phytase and the interaction, influenced digested and retained energy significantly (P<0.05). Therefore, digestibility of energy by broiler chickens fed CSM-based diets supplemented with phytase improved digested and retained energy in broiler chickens.