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Phosphorus utilization and characterization of ileal digesta and excreta from broiler chickens fed diets varying in cereal grain, phosphorus level, and phytase addition

Leytem, A.B. and Widyaratne, G.P. and Thacker, P.A. (2008) Phosphorus utilization and characterization of ileal digesta and excreta from broiler chickens fed diets varying in cereal grain, phosphorus level, and phytase addition. Poultry Science. 87(12):2466-2476.

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Abstract

Both intrinsic and exogenous phytase
in poultry feeds can alter phytate utilization and the
solubility of P excreted. This experiment determined
the effects of feeding diets varying in cereal grain, P
concentration and phytase addition on phytate and P
utilization and P characterization of ileal digesta and
excreta. Twelve treatments, consisting of diets based
on corn, wheat, barley, or high fat-low lignin oat and 3
P treatments (low P with 0.30% nonphytate P; low P
+ 1,000 phytase units of phytase; high P with 0.45%
nonphytate P), were fed to 300 broilers using a factorial
design. Fresh excreta were collected at 20 and 21 d
and ileal digesta was collected at 21 d. Ileal digesta and
excreta were analyzed for total P, phytate P and Ca,
with P composition determined by solution 31P nuclear
magnetic resonance spectroscopy. Excreta samples were
also analyzed for water soluble P (WSP). Apparent ileal
digestibility coefficients for phytate P and total P
ranged from 0.03 to 0.42 and 0.56 to 0.71, respectively.
Diets supplemented with phytase had greater phytate P
hydrolysis than unsupplemented diets. Apparent total
tract digestibility coefficients for phytate P and total P
ranged from 0.10 to 0.73 and 0.43 to 0.61, respectively.
Across cereal grains, there was almost a 3-fold increase
in total tract phytate P hydrolysis with phytase supplementation.
The P composition of ileal digesta was predominantly
phytate P (70 to 88% of total P), whereas
excreta phytate P ranged from 26 to 76% of total P.
Excreta WSP ranged from 3.2 to 7.5 g kg?1 and was
least for the barley diets. There was a 25% reduction in
excreta WSP from the high P to the low P + phytase
diets and a 37% reduction from the high P to the low
P diets. As cereal grain had little influence on phytate
digestibility, it is unlikely that intrinsic phytase in grain
has much influence on phytate utilization by poultry.
Both total P and WSP in excreta were reduced by the
low P diet and the low P + phytase diet, irrespective
of cereal grain, which reduces the risk of P transfer to
water bodies when excreta are applied to land as fertilizer.

Item Type: Article
NWISRL Publication Number: 1302
Subjects: Animal
Soil > Chemistry > Phosphorous
Depositing User: Users 6 not found.
Date Deposited: 30 Nov 2009 21:06
Last Modified: 17 Oct 2016 16:33
Item ID: 1325
URI: https://eprints.nwisrl.ars.usda.gov/id/eprint/1325