Phytase dose-dependent response of kidney inositol phosphate levels in poultry

Abstract

Phytases, enzymes that degrade phytate present in feedstuffs, are widely added to the diets of monogastric animals. Many studies have correlated phytase addition with improved animal productivity and a subset of these have sought to correlate animal performance with phytase-mediated generation of inositol phosphates in different parts of the gastro-intestinal tract or with release of inositol or of phosphate, the absorbable products of phytate degradation. Remarkably, the effect of dietary phytase on tissue inositol phosphates has not been studied. The objective of this study was to determine effect of phytase supplementation on liver and kidney myo-inositol and myo-inositol phosphates in broiler chickens. For this, methods were developed to measure inositol phosphates in chicken tissues. The study comprised wheat/soy-based diets containing one of three levels of phytase (0, 500 and 6,000 FTU/kg of modified E. coli 6-phytase). Diets were provided to broilers for 21 D and on day 21 digesta were collected from the gizzard and ileum. Liver and kidney tissue were harvested. Myo-inositol and inositol phosphates were measured in diet, digesta, liver and kidney. Gizzard and ileal content inositol was increased progressively, and total inositol phosphates reduced progressively, by phytase supplementation. The predominant higher inositol phosphates detected in tissues, D-and/or L-Ins(3,4,5,6)P4 and Ins(1,3,4,5,6)P5, differed from those (D-and/or L-Ins(1,2,3,4)P4, D-and/or L-Ins(1,2,5,6)P4, Ins(1,2,3,4,6)P5, D-and/or L-Ins(1,2,3,4,5)P5 and D-and/or L-Ins(1,2,4,5,6)P5) generated from phytate (InsP6) degradation by E. coli 6-phytase or endogenous feed phytase, suggesting tissue inositol phosphates are not the result of direct absorption. Kidney inositol phosphates were reduced progressively by phytase supplementation. These data suggest that tissue inositol phosphate concentrations can be influenced by dietary phytase inclusion rate and that such effects are tissue specific, though the consequences for physiology of such changes have yet to be elucidated.

Accentuating the positive and eliminating the negative: Efficacy of TiO2 as digestibility index marker for poultry nutrition studies

“…The basal diets were supplemented or not with TiO 2 at 5g/kg. Animals, animal husbandry and basal diet composition of this trial have been described previously in an accompanying study of effect of dietary phytase on tissue inositol phosphates [ 8 ].…”

“…More recently, extremely sensitive detection of inositol phosphates and inositol pyrophosphates has been achieved by combination of TiO 2 -enrichment with mass spectrometry methods [ 7 ]. While there are remarkably few comparative studies of inositol phosphate speciation of different organs or effect of diet thereon, we recently described the use of TiO 2 as solid phase extraction medium with high performance liquid chromatography (HPLC)-based separations for measurements of inositol phosphates in poultry tissues [ 8 ]. The much higher levels of inositol phosphates in avian erythrocytes allow similar measurement without recourse to TiO 2 by employ of HPLC methods that are widely used in poultry nutrition studies for analysis of gizzard and ileal contents [ 9 , 10 ].…”

The phytase RipBL1 enables the assignment of a specific inositol phosphate isomer as a structural component of human kidney stones

“…1,3,4 A variety of analytical methods have been reported, including, for example, strong anion exchange high performance liquid chromatography (SAX-HPLC), high performance liquid chromatography coupled to mass spectrometry (HPLC-MS), and capillary electrophoresis coupled to electrospray ionization mass spectrometry (CE-ESI-MS). [5][6][7][8][9][10][11][12][13] Most of these methods are sensitive and efficient for the analysis of highly phosphorylated InsPs (e.g. InsP 4 , InsP 5 , InsP 6 ).…”

“…InsP 4 , InsP 5 , InsP 6 ). 5–11 Moreover, CE-MS methods are powerful tools for profiling of inositol pyrophosphates (PP-InsPs), such as InsP 7 and InsP 8 that carry one or several diphosphate groups. 6,14–16…”

“…InsP 4 , InsP 5 , InsP 6 ). [5][6][7][8][9][10][11] Moreover, CE-MS methods are powerful tools for profiling of inositol pyrophosphates (PP-InsPs), such as InsP 7 and InsP 8 that carry one or several diphosphate groups. 6,[14][15][16] Analyzing identity and abundance of InsP 1 , InsP 2 and InsP 3 isomers in biological samples remains a significant challenge for several reasons.…”