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Phosphorus composition of manure from swine fed low-phytate grains: Evidence for hydrolysis in the animal

Composición de Fósforo en Abono Porcino alimentados con Granos Bajos en Fitatos: Evidencia de Hidrólisis en el Animal

Leytem, April B. and Turner, Benjamin L. and Thacker, P.A. (2004) Phosphorus composition of manure from swine fed low-phytate grains: Evidence for hydrolysis in the animal. Journal of Environmental Quality. 33:2380-2383.

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Including low-phytic-acid grains in swine diets can reduce P concentrations
in manure, but the influence on manure P composition is
relatively unknown. To address this we analyzed manure from swine
fed one of four barley (Hordeum vulgare L.) varieties. The barley types
consisted of wild-type barley (CDC bold, normal barley diet) and
three low-phytic-acid mutant barleys that contained similar amounts
of total P but less phytic acid. The phytic acid concentrations in the
mutant barleys were reduced by 32% (M422), 59% (M635), and 97%
(M955) compared with that in the wild-type barley, respectively. Phosphorus
concentrations were approximately one-third less in manures
from animals fed low-phytic-acid barleys compared with those fed the
wild-type variety. Phytic acid constituted up to 55% of the Pin feed, but
only trace concentrations were detected in NaOH–EDTA extracts of all
manures by solution 31P nuclear magnetic resonance (NMR) spectroscopy.
Phosphate was the major P fraction in the manures (86-94%
extracted P), with small concentrations of pyrophosphate and simple
phosphate monoesters also present. The latter originated mainly from
the hydrolysis of phospholipids during extraction and analysis. These
results suggest that phytic acid is hydrolyzed in swine, possibly in the
hind gut by intestinal microflora before being excreted in feces, even
though the animals have little phytase activity in the gut and derive
little nutritional benefit from phytate P. We conclude that feeding
low-phytic-acid grains reduces total manure P concentrations and
the manure P is no more soluble than P generated from normal
barley diets.

Item Type: Article
NWISRL Publication Number: 1138
Subjects: Manure > Chemistry
Mass Import - autoclassified (may be erroneous)
Depositing User: Users 5 not found.
Date Deposited: 20 Nov 2010 21:49
Last Modified: 03 Nov 2016 16:13
Item ID: 3