English abstract
Date fiber is one of the cheap and readily available date by-products in
Oman. The aim of this study was to evaluate the potential of partially
replacing corn with date fiber as an alternative energy source in poultry
feeds. Date fiber had higher gross energy than corn by 8.7%, crude fiber by 75%
and lower in total amino acid by 9.1%, lower in indispensable amino acid by
27.2% and higher in dispensable amino acid by 14.7%. An ileal digestibility
assay using 30 birds was carried out to determine the digestibility coefficients
of individual amino acids, crude fiber and apparent metabolizable energy of
date fiber. Date fiber had lower digestibility coefficient than corn for dry
matter (0.35 vs. 0.83), crude fiber (0.20 vs. 0.54) and apparent metabolizable energy contents (8.7 vs. 13.6). Corn had higher digestibility coefficient by 29% and 32% for indispensable and dispensable amino acid respectively
than date fiber. For the most important individual amino acids for bird's and 36%
less digestible performance, the date fiber had 30%, 33% methionine, threonine, and lysine respectively. Based on the results of the preliminarily study, a growth trial was conducted in an attempt to use exogenous enzymes to improve the nutritive value of date fiber in poultry diets. Four hundred birds were divided into eight groups with 10 replicates, each containing 5 birds. Three levels of date fiber (5%, 10% and 15%) with and without enzyme supplementation were evaluated.
Daily feed intake, body weight gain, and feed conversion ratio were measured. At the end of the growth experiment period (42 days), 160 birds were selected randomly and slaughtered to evaluate carcass and meat quality traits, as well as measuring ileal viscosity. Substitution of corn by 10% and 15% date fiber significantly (P<0.05) depressed the apparent metabolizable energy. Apparent metabolizable energy utilization slightly increased as the bird grew older. Enzyme supplementation did not improve the crude fiber digestibility. The inclusion of date fiber in the diets, except at 5% decreased average daily gain, feed intake, and feed conversion ratio. Addition of date fiber caused a significantly increase (P<0.05) in the weights of bird's total digestive tract, pancreas and cecum. Addition of date fiber or exogenous enzyme had no significant effect on carcass or meat quality characteristics. Date fiber increased (P<0.05) the ileal digesta viscosity compared to the control. Addition of exogenous enzyme decreased (P<0,05) the viscosity of the basal diets, as where it has no effect on the date fiber containing diets. This study indicated that date fiber can be included at a
level of 5% in broiler's diets without affecting broiler performance.
