Phytic acid, mineral cations and phytase interactions Roselina Angel – University of Maryland Todd 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

Phytase Phosphate Inositol 5 Phosphate

Background Mineral inhibition of phytase – Maenz et al. (1999) Zn 2+ > > Fe 2+ >Mn 2+ >Fe 3+ >Ca 2+ >Mg 2+ 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) Cu 2+ >Zn 2+ >Ni 2+ >Co 2+ >Mn 2+ >Fe 3+ >Ca 2+ – Maddaiah et al. (1964) Zn 2+ >Cu 2+ >Co 2+ >Mn 2+ >Ca 2+ At the same pH

Cation Inhibition of Phytate Hydrolysis* Maenz et al., 1999 * mM mineral conc. for 50% inhibition

Cation Inhibition of Phytate Hydrolysis* * mM mineral conc. for 50% inhibition Maenz et al., 1999

2 mmol Phytic Acid + 30 mmol Calcium [Corn/SBM dietary phytic acid + 0.9% Calcium (2:1; H 2 0:feed)] Angel and Applegate, 2000

pH = mmol Phytic Acid + 30 mmol Calcium [Corn/SBM dietary phytic acid + 0.9% Calcium (2:1; H 2 0:feed)] Angel and Applegate, 2000

pH = 2.5 pH = mmol Phytic Acid + 30 mmol Calcium [Corn/SBM dietary phytic acid + 0.9% Calcium (2:1; H 2 0:feed)] Angel and Applegate, 2000

pH = 2.5 pH = mmol Phytic Acid + 30 mmol Calcium [Corn/SBM dietary phytic acid + 0.9% Calcium (2:1; H 2 0:feed)] Angel and Applegate, 2000

2 mmol phytic acid+ 30 mmol Calcium [corn/SBM St diet phytic acid content+ 0.9% Ca (2:1; H 2 0:diet)] % 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; H 2 0:diet)] % of the phytic acid P in solution Angel, 2007 Proventriculus/ Gizard Proximal duodenum Distal duodenum to Ileum

Ca & Ileal Phytate-P Hydrolysis: Chick * * Applegate et al., 2003

Ca & Ileal Phytate-P Hydrolysis: Chick Tamim et al 2003, 2004, unpublished Applegate et al., 2003 %

Ca & Ileal Phytate-P Hydrolysis Tamim et al., 2003, 2004, unpublished; Applegate et al., 2003 Exp 1Exp 2Exp 3Exp2Exp (% PP Hydrolysis) % Ca % Ca % Ca % Ca (PP, % of diet) Δ PP hydrolysis

pH = 2.5 pH = 6.5 Phytic Acid ppm Cu (CuSO 4 )

Banks & Applegate, 2003 Phytase U/kg Copper Sulfate addition to Broiler Diets

a,b c a b Banks & Applegate, 2003 Phytase U/kg

Copper Sulfate addition to Broiler Diets a,b c a b Banks & Applegate, 2003 Phytase U/kg (% of diet) (% of diet)

Pang & Applegate, 2004

CuSO 4 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 a c c b b ppm Cu b 0.20 nPP 0.40 nPP a-c: P ≤ 0.05 Sulfate Citrate Lysinate Chloride Banks & Applegate, 2004

Ca & Micro-mineral source – in vivo Phytate – P hydrolysis % Calcium % Calcium Tamim & Angel, 2003 Ca: P < Micro mineral: P=0.39 Ca*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)