Crude protein digestibility in broiler chickens fed rice husk-based diets supplemented with phytase

Abstract

A total of 288, one day-old Arbor acres broiler chicks (BC) fed broiler starter till day 20 were used to investigate the effect of phytase on the digestibility of crude protein. 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 in the freezer 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 semi-purified diets with 150, 300 and 450g/kg rice husk (RH) and 0 or 1000 units of phytase (Natuphos) were formulated. Ileal crude protein (CP) of the birds was significantly (P< 0.05) reduced by feeding graded levels of RH, while interaction of phytase and CP had no significant effect on the excreta CP (P>0.05). Apparent CP digestibility and retention of the birds had no linear and quadratic (P>0.05) responses as the dietary supply of protein from RH increase. Increasing dietary concentration of protein intake from RH, addition of phytase and the interaction, influenced digested and retained CP significantly (P<0.05). Therefore, digestibility of crude protein by broiler chickens fed RH-based diets supplemented with phytase improved digested and retained crude protein in broiler chickens.