Phytic acid is the main storage of P in plants, and most P in plant feed ingredients is bound in the phytate complex. Because pigs do not secrete phytase, an enzyme to hydrolyze inositol bonds in phytate, the utilization of P by pigs is very low. Addition of supplemental phytase to diets thus results in release of P and increases P utilization by pigs. However, all enzymes have a special recognition mechanism called specificity that works only with molecules that fit to active sites of the enzyme. Therefore, it is important to know how much of P is phytate-bound and how much of the P in a given diet is not phytate-bound.
Among all experiments that have been conducted at the University of Illinois (i.e., Stein Monogastric Laboratory), 47 peer-reviewed articles published between 2011 and 2020 and 34 unpublished experiments had data for analyzed values for phytate and P. In these experiments, 46 different feed ingredients were analyzed. Concentration of P was analyzed using inductively coupled plasma spectroscopy (method 985.01 A, B, and C; AOAC, 2019). Phytic acid in feed ingredients was also analyzed using the method described by Ellis et al. (1977). Phytate-P was calculated by multiplying the analyzed phytate by 0.282 (Tran and Sauvant, 2004).
Concentration of P in the 46 feed ingredients ranged from 0.11 (broken rice) to 2.35% (defatted rice bran) and concentration of phytate ranged from 0.14 (low oil DDGS) to 7.52% (defatted rice bran; Table 1). Comparative concentration of phytate in feed ingredients between book values (NRC, 2012) and values obtained from Stein Monogastric Laboratory is also provided (Table 2).
Literature Cited
AOAC Int. 2019. Official methods of analysis of AOAC Int. 21th ed. AOAC Int., Rockville, MD, USA.
Ellis, R., E. R. Morris, and C. Philpot. 1977. Quantitative determination of phytate in presence of high inorganic-phosphate. Anal. Biochem. 77:536-539. doi:10.1016/0003-2697(77)90269-X.
NRC. 2012. Nutrient requirements of swine. 11th rev. ed. Natl. Acad. Press, Washington, DC, USA.
Tran, G., and D. Sauvant. 2004. Chemical data and nutritional value. In: A. Ponter, D. Sauvant, J.-M. Perez and G. Tran, editors, Tables of composition and nutritional value of feed materials: pigs, poultry, cattle, sheep, goats, rabbits, horses and fish. Wageningen Academic Publishers, Wageningen, the Netherlands. p. 17-24.
Table 1. Concentrations of P, phytate, phytate-P, and non-phytate P in feed ingredients used in experiments conducted at the University of Illinois
|
Feed ingredient |
n |
P, % |
Phytate, % |
Phytate-P, % |
Non- phytate P, % |
|---|---|---|---|---|---|
|
Bakery meal |
55 |
0.33 |
0.65 |
0.18 |
0.15 |
|
Barley |
2 |
0.32 |
0.71 |
0.20 |
0.12 |
|
Canola expellers |
10 |
1.09 |
3.15 |
0.89 |
0.20 |
|
Canola meal |
77 |
1.12 |
3.09 |
0.87 |
0.25 |
|
Copra expellers |
3 |
0.51 |
0.90 |
0.25 |
0.26 |
|
Copra meal |
4 |
0.52 |
0.79 |
0.22 |
0.30 |
|
Corn |
30 |
0.25 |
0.65 |
0.18 |
0.06 |
|
Corn germ |
3 |
1.13 |
2.97 |
0.84 |
0.29 |
|
Corn germ meal |
5 |
0.79 |
1.90 |
0.54 |
0.26 |
|
Corn gluten feed |
3 |
0.87 |
0.71 |
0.20 |
0.67 |
|
Corn gluten meal |
6 |
0.56 |
1.66 |
0.47 |
0.09 |
|
Corn DDGS, high-oil, >9% oil |
6 |
0.81 |
0.53 |
0.15 |
0.66 |
|
Corn DDGS, defatted, < 5% oil |
1 |
1.01 |
0.14 |
0.04 |
0.97 |
|
Corn DDGS, low oil, 5-9% oil |
6 |
0.82 |
1.14 |
0.32 |
0.50 |
|
Corn, hominy feed |
1 |
0.70 |
2.07 |
0.58 |
0.12 |
|
Corn DDG, high protein |
2 |
0.38 |
0.41 |
0.11 |
0.27 |
|
Cottonseed meal |
2 |
1.14 |
2.65 |
0.75 |
0.42 |
|
Field peas |
1 |
0.42 |
0.73 |
0.17 |
0.25 |
|
Hybrid rye |
5 |
0.28 |
0.74 |
0.21 |
0.07 |
|
Lemna protein concentrate |
2 |
0.51 |
0.15 |
0.04 |
0.47 |
|
Oat |
1 |
0.32 |
0.67 |
0.19 |
0.13 |
|
Palm kernel expellers |
4 |
0.53 |
1.25 |
0.36 |
0.17 |
|
Palm kernel meal |
3 |
0.53 |
1.18 |
0.33 |
0.20 |
|
Potato protein concentrate (isolate) |
7 |
0.13 |
0.33 |
0.09 |
0.04 |
|
Rice bran, full fat |
3 |
1.91 |
5.94 |
1.66 |
0.26 |
|
Rice bran, defatted |
3 |
2.35 |
7.52 |
2.11 |
0.23 |
|
Rice mill feed |
1 |
0.63 |
2.01 |
0.56 |
0.07 |
|
Rice, broken |
2 |
0.11 |
0.22 |
0.06 |
0.05 |
|
Rice, brown |
2 |
0.27 |
0.79 |
0.22 |
0.05 |
|
Sorghum |
6 |
0.30 |
0.80 |
0.23 |
0.08 |
|
Soy protein concentrate |
1 |
0.62 |
1.41 |
0.39 |
0.23 |
|
Soybean meal, high CP (CP ≥ 47%) |
51 |
0.64 |
1.56 |
0.44 |
0.21 |
|
Soybean meal, low CP (CP < 47%) |
30 |
0.63 |
1.66 |
0.47 |
0.16 |
|
Soybean expellers |
4 |
0.78 |
1.36 |
0.38 |
0.40 |
|
Soybean meal, fermented |
7 |
0.60 |
0.88 |
0.25 |
0.35 |
|
Sugar beet pulp |
2 |
0.70 |
0.14 |
0.04 |
0.66 |
|
Sunflower expellers |
1 |
0.48 |
1.99 |
0.56 |
0.00 |
|
Sunflower meal, partially dehulled |
9 |
0.93 |
2.88 |
0.81 |
0.13 |
|
Sunflower, full fat |
1 |
0.70 |
1.80 |
0.51 |
0.19 |
|
Triticale |
1 |
0.38 |
0.74 |
0.21 |
0.17 |
|
Wheat |
2 |
0.38 |
0.97 |
0.27 |
0.11 |
|
Wheat germ |
1 |
0.88 |
2.06 |
0.58 |
0.30 |
|
Wheat, hard red |
2 |
0.36 |
0.89 |
0.25 |
0.11 |
|
Wheat, soft red |
1 |
0.36 |
1.15 |
0.32 |
0.04 |
|
Yeast brewers |
1 |
1.40 |
1.03 |
0.29 |
1.11 |
| Yeast, torula | 1 | 1.78 | 0.25 | 0.07 | 1.74 |
|
|
|
|
|
|
|
Table 2. Comparative concentration of phytate in feed ingredients
|
Item, % |
NRC, 2012 |
Stein Monogastric Laboratory |
|---|---|---|
|
Bakery meal |
- |
0.65 |
|
Barley |
0.78 |
0.71 |
|
Barley, dehulled |
0.92 |
- |
|
Canola expellers |
3.09 |
3.15 |
|
Canola meal |
2.3 |
3.09 |
|
Copra expellers |
0.78 |
0.90 |
|
Copra meal |
0.92 |
0.79 |
|
Corn |
0.74 |
0.65 |
|
Corn DDGS, high-oil, >9% oil |
0.92 |
0.53 |
|
Corn DDGS, defatted, < 5% oil |
- |
0.14 |
|
Corn DDGS, low oil, 5-9% oil |
- |
1.14 |
|
Corn germ |
3.79 |
2.97 |
|
Corn germ meal |
- |
1.90 |
|
Corn gluten feed |
2.20 |
0.71 |
|
Corn gluten meal |
- |
1.66 |
|
Corn, hominy feed |
1.74 |
2.07 |
|
Corn DDG, high protein |
0.39 |
0.41 |
|
Corn, nutridense |
0.57 |
- |
|
Cottonseed meal |
- |
2.65 |
|
Field peas |
0.60 |
0.73 |
|
Lemna protein concentrate |
- |
0.15 |
|
Lupins |
0.74 |
- |
|
Molasses, sugarcane |
0.04 |
- |
|
Oat |
0.67 |
0.67 |
|
Palm kernel expellers |
1.31 |
1.25 |
|
Palm kernel meal |
1.10 |
1.18 |
|
Potato protein concentrate/isolate |
- |
0.33 |
|
Rice, broken |
0.50 |
0.22 |
|
Rice, brown |
- |
0.79 |
|
Rice bran |
6.17 |
5.94 |
|
Rice bran, defatted |
- |
7.52 |
|
Rice mill feed |
- |
2.01 |
|
Rye |
0.71 |
- |
|
Rye, hybrid |
- |
0.74 |
|
Sesame meal |
3.16 |
- |
|
Sorghum |
0.64 |
0.80 |
|
Soy protein concentrate |
- |
1.41 |
|
Soybeans, full fat |
1.17 |
- |
|
Soybean meal, high CP (CP ≥ 47%) |
1.35 |
1.56 |
|
Soybean meal, low CP (CP < 47%) |
1.28 |
1.66 |
|
Soybean expellers |
- |
1.36 |
|
Soybean meal, fermented |
- |
0.88 |
|
Soybean hulls |
0.28 |
- |
|
Sugar beet pulp |
- |
0.14 |
|
Sunflower, full fat |
- |
1.80 |
|
Sunflower expellers |
- |
1.99 |
|
Sunflower meal, partially dehulled |
3.16 |
2.88 |
|
Triticale |
0.74 |
0.74 |
|
Wheat |
- |
0.97 |
|
Wheat, hard red |
0.78 |
0.89 |
|
Wheat, soft red |
0.71 |
1.15 |
|
Wheat bran |
3.12 |
- |
|
Wheat, DDGS |
0.74 |
- |
|
Wheat germ |
- |
2.06 |
|
Wheat middlings |
2.16 |
- |
|
Yeast, brewers |
- |
1.03 |
|
Yeast, torula |
- |
0.25 |
|
|
|
|
|---|