Mineral Utilization Phytate is a potent chelator of minerals, particularly cations which are attracted to the highly negative charge on IP6. Similar to positive and negative charges on magnets, IP6 attracts positively charged minerals such as iron (Fe; Yu et al., 2012), zinc (Zn), and calcium (Ca; Xu et al., 1992) and renders them unavailable for digestion and absorption by the animal. When discussing IP6 and minerals, we generally refer to intact phytate with all 6-phosphate esters (IP6). However, through the action of phytase on IP6, smaller phytate esters are formed such as IP5, IP4 and IP3 (Greiner et al., 1993). These esters are thought to be innocuous and less of an anti-nutrient than IP6. However, this may not be the case and the smaller phytate esters have been reported to influence pepsin activity (Yu et al., 2012) and Cu (Persson et al., 1998), Zn and Ca (Xu et al., 1992) solubility, which may subsequently have an influence on utilization by the animal. In addition, through the use of standard doses of phytase,
significant quantities of IP6 are broken down to create IP4 through the removal of two phosphate groups (Greiner et al., 1993; Yu et al., 2012). As mentioned previously, this created IP4 may also be considered an anti-nutrient, as IP4 also has the capacity to bind minerals and pepsin, albeit not to the same extent as IP6. Through the use of superdoses of phytase there is a rapid and nearly complete destruction of IP6 in the gizzard and no effect (Walk et al., 2014) or a significant reduction in the concentration of IP4 (C. Walk and D. Ledoux, unpublished; Table 2) in the gizzard. When compared with standard doses of phytase, previous
Table 2: Influence of Phytase Dose on Phytate, Phytate Esters or Inositol Concentration in the Gizzard of 21 Day-Old Broilers
Experimental diets
PC1 NC2
NC + 150 FTU NC + 1,500 FTU SEM
P-value 1
IP6,
µmol/g 4.66b 5.71a 0.20c 0.07c 0.22
0.0001 IP5,
µmol/g 0.55b 0.67a 0.05c 0.02c 0.03
0.0001 IP4,
nmol/g 69.63b 17.75b 307.4a 0.63b 90.2
0.0001
Negative control, nutrient adequate according to breed recommendations with the exception of Ca and available P which was reduced 0.12 and 0.07%, respectively.
Positive control, nutrient adequate according to breed recommendations. 2
Inositol, µmol/g
0.36c 0.45c 0.90b 2.40a 0.07
0.0001
authors have reported significant improvements not only in phytate P utilization (Beeson et al., 2015, 2016) but also in micro-mineral utilization (Pirgozliev et al., 2008; Rutherfurd et al., 2012) and bone mineral content (Williams et al., 2014) through the use of superdoses of phytase. These results confirm previous reports that phytase can improve micro- and macro-mineral utilization, and the use of superdoses of phytase results in rapid destruction of IP6 as well as IP4. This may be beneficial by further improving mineral utilization, including P, and thereby allowing for a further reduction in inorganic P in the diet (Table 3; Gomes et al., unpublished) or even a reduction of other supplemental micro-minerals. These improvements in mineral
Table 3: Phytase Superdose Allows for a Significant Reduction in Inorganic Phosphorus Without Negatively Influencing Growth Performance (0-42 days) or Tibia Ash (at 21 days)
Phase 1 Trial 11
1.56 0.75 0.51 0.35
Trial 22
1.64 0.88 0.63 0.37 0.20
1.42 0.71 0.47 0.24 0.00
1.20 0.60 0.40 0.20 0.00
1 Within each phase, the difference in dicalcium PO 4 Within each phase, the difference in dicalcium PO 4 0
250 500
1,000 1,500
P-value
3,376bc 3,355c 3,424ab 3,428ab 3,449a 0.03
Diets were composed of corn and soybean meal and were fed from hatch to 42d post-hatch. 2
1.60 1.60 1.59 1.58 1.58 0.09
51.9 51.5 51.6 51.4 51.1 0.80
corresponds to a reduction in available P from the diet by 0.15, 0.195 and 0.225%. corresponds to a reduction in available P from the diet by 0.12, 0.16, 0.20 and 0.24%. Diets were composed of corn, rice polishings and soybean meal, and were fed from hatch to 42d post hatch. FEED COMPOUNDER MAY/JUNE 2017 PAGE 43
1.34 0.53 0.29 0.13
1.22 0.41 0.16 0.00
0 500
1,000 1,500
P-value
2,785 2,838 2,765 2,886 0.09
1.67 1.65 1.66 1.64 0.41
50.3 48.5 48.9 48.5 0.48
Dicalcium PO4 Phase 2
, % Phase 3 Phytase, FTU/kg BWG, g FCR, g:g Tibia Ash, %
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