phytic acid, mineral cations and phytase interactions roselina angel – university of maryland todd...
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Phytic acid, mineral cations and phytase interactions
Roselina Angel – University of MarylandTodd Applegate – Purdue University
Phytic Acid
P C H O
Ca
Protein
Cu
Starch
Zn
Fe
Protein
Cation “Impairment” of P hydrolysis
vs.Cation “release” capacity of
phytase
Background
• Mineral inhibition of phytase– Maenz et al. (1999)
• Zn2+ > > Fe2+ >Mn2+ >Fe3+ >Ca2+ >Mg2+
• Soluble Ca - chelate at 1 mM Ca : 10 mM phytate• Soluble Zn - chelate at equal concentrations Zn : phytate
• Mineral complex stability– Vohra et al. (1965)
• Cu2+ >Zn2+ >Ni2+ >Co2+ >Mn2+ >Fe3+ >Ca2+
– Maddaiah et al. (1964)• Zn2+ >Cu2+ >Co2+ >Mn2+ >Ca2+
• At the same pH
Cation Inhibition of Phytate Hydrolysis*
0
0.4
0.8
1.2
1.6
4 5 6 6.5 7
pH
Zn
(mM
)
0
40
80
120
Zn++ Ca++
Maenz et al., 1999* mM mineral conc. for 50% inhibition
Cation Inhibition of Phytate Hydrolysis*
0
0.4
0.8
1.2
1.6
4 5 6 6.5 7
pH
Zn
(mM
)
0
40
80
120
Ca
(mM
)
Zn++ Ca++
* mM mineral conc. for 50% inhibitionMaenz et al., 1999
2 mmol Phytic Acid + 30 mmol Calcium[Corn/SBM dietary phytic acid + 0.9% Calcium (2:1; H20:feed)]
Angel and Applegate, 2000
pH = 2.5
2 mmol Phytic Acid + 30 mmol Calcium[Corn/SBM dietary phytic acid + 0.9% Calcium (2:1; H20:feed)]
Angel and Applegate, 2000
pH = 2.5 pH = 6.5
2 mmol Phytic Acid + 30 mmol Calcium[Corn/SBM dietary phytic acid + 0.9% Calcium (2:1; H20:feed)]
Angel and Applegate, 2000
pH = 2.5 pH = 6.5
2 mmol Phytic Acid + 30 mmol Calcium[Corn/SBM dietary phytic acid + 0.9% Calcium (2:1; H20:feed)]
Angel and Applegate, 2000
2 mmol phytic acid+ 30 mmol Calcium[corn/SBM St diet phytic acid content+ 0.9% Ca (2:1; H20:diet)]
100 100 100 97.9 84.7 62.1 51.7 26.4 11.1 7.9 1.5
% of the phytic acid P in solution
Angel, 2007
2 mmol Phytic Acid+ 30 mmol Calcium[Corn/SBM St diet phytic acid content + 0.9% Ca (2:1; H20:diet)]
100 100 100 97.9 84.7 62.1 51.7 26.4 11.1 7.9 1.5% of the phytic acid P in solution
Angel, 2007
Proventriculus/ Gizard
Proximal duodenum
Distal duodenum to Ileum
Ca & Ileal Phytate-P Hydrolysis: Chick
01020304050607080
Exp. 2 Exp. 3
% P
hyta
te P
Hyd
roly
sis
0.4 % Ca 0.9 % Ca
*
*
Applegate et al., 2003
Ca & Ileal Phytate-P Hydrolysis: Chick
15
25
35
45
55
65
75
Exp 1 Exp 2 Exp 3 Exp 2 Exp 3
0.2% Ca
0.4% Ca
0.7% Ca
0.9% Ca
Tamim et al 2003, 2004, unpublished Applegate et al., 2003
%
Ca & Ileal Phytate-P Hydrolysis
Tamim et al., 2003, 2004, unpublished; Applegate et al., 2003
Exp 1 Exp 2 Exp 3 Exp2 Exp3
--------------------------- (% PP Hydrolysis)-------------------
0.2% Ca 67.1 69.2 68.9
0.4% Ca 74.1 35.2
0.7% Ca 18.9 25.4 28.5
0.9% Ca 49.7 23.1
------------------------------- (PP, % of diet) ------------------------
Δ PP hydrolysis - 0.13 - 0.12 - 0.11 - 0.063 -0.031
15
25
35
45
55
65
75
Exp 1 Exp 2 Exp 3 Exp 2 Exp 3
0.2% Ca
0.4% Ca
0.7% Ca
0.9% Ca
pH = 2.5 pH = 6.5
Phytic Acid + 250 ppm Cu (CuSO4)
35
40
45
50
55
60
65
0 600
% p
hosp
horu
s re
tent
ion
no copper sulfate 2 lb/ton copper sulfate
Banks & Applegate, 2003Phytase U/kg
Copper Sulfate addition to Broiler Diets
Copper Sulfate addition to Broiler Diets
35
40
45
50
55
60
65
0 600
% p
hosp
horu
s re
tent
ion
no copper sulfate 2 lb/ton copper sulfate
a,b
c
a
b
Banks & Applegate, 2003Phytase U/kg
Copper Sulfate addition to Broiler Diets
35
40
45
50
55
60
65
0 600
% p
hosp
horu
s re
tent
ion
no copper sulfate 2 lb/ton copper sulfate
a,b
c
a
b
Banks & Applegate, 2003Phytase U/kg
-0.066 (% of diet)
-0.055 (% of diet)
Solubility of different Cu sources at different
concentrations at pH6.5
0
20
40
60
80
100
120
Cu Sul Cu CL TBCC Cu Lys Cu CIT
Cu sources
So
lub
ility
(%) 62.5
125
250
500
Pang & Applegate, 2004
0
20
40
60
80
100
120
0 1 2 3 4 5 6
Re
lativ
e P
re
lea
se (
%)
0 62.5 125 250 500
CuSO4 CuCl TBCC Cu-Lys Cu-Citrate
Cu source & Phytase activity – pH6.5
Pang & Applegate, 2004
Apparent Phosphorus Retention (% of diet) as affected by Cu source
0
10
20
30
40% P Retention
a
cc
b b
0 0 250 250 250 250 ppm Cu
b
0.20
nPP
0.40
nPP
a-c: P ≤ 0.05
Su
lfate
Citrate
Lysin
ate
Ch
loride
Banks & Applegate, 2004
Ca & Micro-mineral source – in vivo Phytate – P hydrolysis
------ 0 % Calcium ------ ------ 0.5 % Calcium ------
Tamim & Angel, 2003
Ca: P < 0.0001Micro mineral: P=0.39Ca*Micro: P = 0.63
Conclusions(& Unresolved questions…….)
a) Calcium has a huge impact on PP hydrolysis. This effect is heavily affected by pH --- but even at acidic pHs it can influence PP hydrolysis by phytase
b) In laying hens vs chicks – lower impact of phytase on PP release. Possibly because of better PP hydrolysis in the absence of phytase
c) Cu (up to 250 ppm) & Zn (up to 160 ppm) have inconsistent impacts on PP hydrolysis & no effect on phytase efficacy (i.e. no interaction of phytase * Cu –or- phytase * Zn)