Influence of Phytase Addition to Poultry Diets on Phosphorus Forms and Solubility in Litters and Amended Soils

Abstract

Diet modification to decrease phosphorus (P) concentration in animal feeds and manures can reduce surpluses of manure P in areas of intensive animal production. We generated turkey and broiler litters from two and three flock trials, respectively, using diets that ranged from "high" to "low" in non-phytate phosphorus (NPP) and some of which contained feed additives such as phytase. Phosphorus forms in selected litters were analyzed by sequential chemical fractionation and solution (31)P nuclear magnetic resonance (NMR) spectroscopy. Selected litters were also incubated with four contrasting soils. Reducing dietary NPP and using phytase decreased total P in litters by up to 38%. Water-soluble phosphorus (WSP) in litters was decreased 21 to 44% by feeding NPP closer to animal requirement, but was not affected by phytase addition. Solution (31)P NMR spectroscopy showed that feeding NPP closer to requirement decreased orthophosphate in litters by an average of 38% and that adding phytase to feed did not increase the concentration of orthophosphate in litters. Phytase also decreased phytate P in litters by 25 to 38%, demonstrating that it increases phytate P hydrolysis. Incorporation of litters with soils at the same total P rate increased WSP in soils relative to the control; this increase was correlated to soluble P added with litters at 5 d, but not by 29 d. Changes in soil Mehlich-3 phosphorus (M3-P) were related to total P added in litter, rather than soluble P. We conclude that feeding NPP closer to requirement and using feed additives such as phytase decrease total P concentrations in litters, while having little effect on P solubility in litters and amended soils.

Phytate utilization and phosphorus excretion by broiler chickens fed diets containing cereal grains varying in phytate and phytase content

“…This finding supports previous work where analysis of excreta from broilers fed diets containing various cultivars of barley revealed that only trace amounts of phytate P were excreted, irrespective of the phytate P concentration of the initial feed (Leytem et al, 2007). However, as the diets in the studies by Maguire et al (2004) and Leytem et al (2006) also contained appreciable amounts of inorganic Ca and P, it could be expected that differences in the proportion of phytate P in the excreta were due to the detrimental effects of these minerals on intestinal phytate P hydrolysis.…”

“…Maguire et al (2004) reported that litter from birds fed maize-based diets contained 0.26-0.56 of P as phytate P, while concentrations in manure from layers fed maize-based diets ranged from 0.35 to 0.80 of total P (Leytem et al, 2006). Based on these findings, it was expected that there would be reasonable concentrations of phytate P in the excreta in the present study.…”

Phosphorus characterization in feces from broiler chicks fed low‐phytate barley diets

“…' 6 Poultry litter (feces mixed with bedding material) and manure can contain high concentrations of phytate. For example, Maguire et al 4 reported that litter from broilers and turkeys fed corn-based diets contained between 26 and 56% of total P as phytate, while Leytem et al 17 reported that phytate concentrations in manures from layers fed corn based diets ranged from 35 to 80% of total P. However, recent analysis of pigs fed diets containing various cultivars of barley revealed that only trace amounts of phytate were excreted, irrespective of the phytate concentration of the initial feed." Clearly, our understanding of the metabolism of phytate in monogamic animals is limited and information is needed on the P composition of feces obtained from a wide range of animals and diets.…”

Environmental implications of inositol phosphates in animal manures.

“…Solution 31 P NMR spectroscopy has been used to quantify the phosphorus composition of a wide variety of manures (Leinweber et al, 1997;1,eytem et al, 2004;Maguire et al, 2004;Turner and Leytem, 2004;McGrath et al, 2005). These studies indicate that manure phosphorus is predominately inorganic phosphate, followed in descending order by phosphate monoesters, phosphate diesters (nucleic acids and phospholipid), pyrophosphates and, in some cases, phosphonates.…”

“…Therefore, after 150 days of storage, there was no significant difference in myo-inositol hexakisphosphate concentrations in swine manures from the two diets. Maguire et al (2004) grew three flocks of broilers and two flocks of turkeys on the same bed of litter using diets that were 'high' and 'low' in non-phytate phosphorus with and without phytase additions. Concentrations of myo-inositol hexakisphosphate in both broiler and turkey litters from diets that included phytase were consistently lower than in litters from equivalent non-phytase diets ( (2005) analysed turkey manure and broiler litter samples from diets with and without phytase using X-ray absorption near-edge structure spectroscopy.…”