What aspect of dietary modification in broilers controls litter water-soluble phosphorus: Dietary phosphorus, phytase, or calcium?

Leytem, A.B. and Plumstead, P.W. and Maguire, R.O. and Kwanyuen, P. and Brake, J. (2007) What aspect of dietary modification in broilers controls litter water-soluble phosphorus: Dietary phosphorus, phytase, or calcium? Journal of Environmental Quality. 36:453-463.

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Abstract

Environmental concerns about phosphorus (P) losses from animal
agriculture have led to interest in dietary strategies to reduce the concentration
and solubility of P in manures and litters. To address
the effects of dietary available phosphorus (AvP), calcium (Ca), and
phytase on P excretion in broilers, 18 dietary treatments were applied
in a randomized complete block design to each of four replicate pens
of 28 broilers from 18 to 42 d of age. Treatments consisted of three
levels of AvP (3.5, 3.0, and 2.5 g kg -1) combined with three levels of
Ca (8.0, 6.9, and 5.7 g kg-1) and two levels of phytase (0 and 600
phytase units [FTU]). Phytase was added at the expense of 1.0 g kg -1
P from dicalcium phosphate. Fresh litter was collected from pens
when the broilers were 41 d of age and analyzed for total P, soluble P,
and phytate P as well as P composition by 31P nuclear magnetic resonance
(NMR) spectroscopy. Results indicated that the inclusion of
phytase at the expense of inorganic P or reductions in AvP decreased
litter total P by 28 to 43%. Litter water-soluble P (WSP) decreased
by up to 73% with an increasing dietary Ca/AvP ratio, irrespective of
phytase addition. The ratio of WSP/total P in litter decreased as the
dietary Ca/AvP ratio increased and was greater in the phytase-amended
diets. This study indicated that while feeding reduced AvP
diets with phytase decreased litter total P, the ratio of Ca/AvP in the
diet was primarily responsible for effects on WSP. This is important
from an environmental perspective as the amount of WSP in litter
could be related to potential for off-site P losses following land application
of litter.

Item Type:	Article
NWISRL Publication Number:	1200
Subjects:	Manure > Chemistry Mass Import - autoclassified (may be erroneous)
Depositing User:	Users 5 not found.
Date Deposited:	20 Nov 2010 21:49
Last Modified:	01 Nov 2016 15:22
Item ID:	45
URI:	https://eprints.nwisrl.ars.usda.gov/id/eprint/45