Phytase

Influence of a novel consensus bacterial 6-phytase variant on mineral digestibility and bone ash in young growing pigs fed diets with different concentrations of phytate

Microbial phytase is usually included in diets for pigs to increase P absorption and utilization by hydrolyzing phytate within the gastrointestinal tract of pigs. High doses of phytase (i.e., > 1,000 FTU/kg) is also hypothesized to increase release of nutrients other than P due to increased degradation of phytate. A next generation biosynthetic bacterial 6-phytase (PhyG; DuPont Animal Nutrition) may increase digestibility of nutrients in diets for pigs; however, there are no data to demonstrate the efficacy of this phytase. Therefore, an experiment was conducted to test the hypothesis that the negative impact of phytate is reduced at higher phytase doses. It was also the objective of this research to test the hypothesis that inclusion of increasing levels of phytase increases bone ash and apparent total tract digestibility (ATTD) of minerals in diets containing varying phytate concentrations.

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Effect of formulating diets based on a ratio between STTD Ca and STTD P and the inclusion of phytase on the calcium and phosphorus balance of growing pigs

Several experiments were conducted to estimate Ca digestibility in different feed ingredients in the presence or absence of microbial phytase to allow formulation of diets for pigs to be based on standardized total tract digestible (STTD) Ca instead of total Ca. Thus, 4 experiments aimed at determining Ca requirements expressed as a ratio between STTD Ca and STTD P in pigs from 11 to 130 kg. A follow-up study was later conducted to validate those data and to evaluate the effect of using ratios that maximize growth performance on bone development because maximum bone ash requires more Ca than maximum growth performance. However, data indicate that STTD Ca to STTD P ratios to maximize Ca retention are greater than to maximize bone ash synthesis. The use of STTD Ca to STTD P ratios in diet formulation may result in a reduction in excess dietary Ca, which is beneficial because excess dietary Ca is detrimental to P digestibility and growth performance of pigs. Therefore, the objective of this experiment was to test the hypothesis that formulating diets for growing pigs based on a ratio between STTD Ca and STTD P instead of total Ca and STTD P does not decrease Ca retention, but increases P utilization.

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Effect of formulating diets based on a ratio between STTD Ca and STTD P and the inclusion of phytase on growth performance, bone ash, plasma Ca and P, and carcass characteristics of pigs from 11 to 130 kg

Calcium requirements by pigs are expressed as total Ca because of a lack of data for the digestibility of Ca in feed ingredients, but it is believed that a ratio between standardized total tract digestible (STTD) Ca and STTD P is a more appropriate way to express requirements for Ca by pigs. Values for Ca digestibility in different Ca-containing feed ingredients were recently generated using diets without or with microbial phytase, which allowed for the formulation of diets based on STTD Ca values. A number of experiments were also conducted to determine STTD Ca to STTD P requirements to optimize growth performance and bone mineralization of pigs from 11 to 25 kg, 25 to 50 kg, 50 to 85 kg, and 100 to 130 kg. However, these experiments were performed independently and in experiments lasting only 3 to 5 weeks. Therefore, a follow-up experiment was conducted to test the hypothesis that the requirement for Ca expressed as a ratio between STTD Ca and STTD P obtained in short-term experiments may be applied to pigs fed diets without or with microbial phytase from 11 to 130 kg.

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Effects of super dosing 4 different sources of phytase on amino acid digestibility

Dietary phytate may bind to proteins from feed ingredients by making indigestible nutrient-complexes. Therefore, it is possible that adding exogenous phytase to the diets increases digestibility of amino acids (AA). However, results of experiments in which microbial phytase has been added to diets fed to pigs have not consistently demonstrated increased ileal digestibility of AA. It is, however, possible that is because the dose of phytase was too low to obtain a positive effect on AA digestibility and that if greater doses were used, a positive response would be obtained. Therefore, the objective of this experiment was to test the hypothesis that super dosing four different sources of commercially available exogenous phytase increases the apparent ileal digestibility (AID) of CP and AA in a corn-soybean meal (SBM) based diet fed to growing pigs.

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Effects of graded levels of phytase on digestibility of nutrients, growth performance, and bone ash in corn and soybean meal based diets fed to pigs

Lee, S. A., and H. H. Stein. 2019. Effects of graded levels of phytase on digestibility of nutrients, growth performance, and bone ash in corn and soybean meal based diets fed to pigs. In: 80th Minnesota Nutrition Conference, Mankato, MN, Sep. 18-19, 2019. P. 25. (Abstr.). Link to abstract

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PSIV-13 Basal endogenous loss, standardized total tract digestibility, and retention of Ca in sows change throughout gestation, but microbial phytase reduces basal endogenous loss of Ca by gestating sows

Lee Su A., Carrie L. Walk, Hans H. Stein. 2019. PSIV-13 Basal endogenous loss, standardized total tract digestibility, and retention of Ca in sows change throughout gestation, but microbial phytase reduces basal endogenous loss of Ca by gestating sows. Journal of Animal Science, Volume 97, Issue Supplement_2, July 2019, Pages 185–186. (Abstr.). Link to abstract.

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PSIII-18 Standardized total tract digestibility of Ca by growing pigs in different sources of calcium carbonate and dicalcium phosphate

Lee Su A., Carrie L. Walk, Hans H. Stein. 2019. PSIII-18 Standardized total tract digestibility of Ca by growing pigs in different sources of calcium carbonate and dicalcium phosphate. Journal of Animal Science, Volume 97, Issue Supplement_2, July 2019, Pages 173–174. (Abstr.). Link to abstract.

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Effects of a novel corn-expressed E. coli phytase on digestibility of calcium and phosphorous, growth performance, and bone ash in young growing pigs

Blavi, Laia, Cristhiam J. Muñoz, Jonathan N. Broomhead, and Hans H. Stein. 2019. Effects of a novel corn-expressed E. coli phytase on digestibility of calcium and phosphorous, growth performance, and bone ash in young growing pigs. J. Anim. Sci. 2019.97:3390–3398. Link to full text.

Standardized total tract digestibility of calcium varies among sources of calcium carbonate, but not among sources of dicalcium phosphate, but microbial phytase increases calcium digestibility in calcium carbonate

Lee, Su A, L. Vanessa Lagos, Carrie L. Walk, and Hans H. Stein. 2019. Standardized total tract digestibility of calcium varies among sources of calcium carbonate, but not among sources of dicalcium phosphate, but microbial phytase increases calcium digestibility in calcium carbonate. J. Anim. Sci. 2019.97:3440–3450.

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Phosphorus and energy digestibility of Fermex 200 (fermented soybean meal) fed to weanling pigs

Soybean meal (SBM) is one of the most important protein sources in swine diets. However, most P in SBM is bound to phytate, which increases inclusion of inorganic P in diets for pigs. Use of microbial phytase may hydrolyze phytate and subsequently improve P absorption. Fermex 200 (Purina Animal Nutrition, Shoreview, MN, USA) is a new source of fermented SBM that may serve as an alternative to other protein sources in diets fed to pigs. However, there are at this point no data for effects of adding phytase to diets containing Fermex 200 and no data for digestible energy (DE) and metabolizable energy (ME) concentrations of Fermex 200.

Therefore, 2 experiments were conducted to test the hypothesis that inclusion of 1,000 phytase units (FTU)/kg of microbial phytase improves the standardized total tract digestibility (STTD) of P in conventional SBM and Fermex 200. The second hypothesis was that the STTD of P, as well as concentrations of DE and ME in Fermex 200 are greater than in conventional SBM.

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Zinc oxide and microbial phytase may reduce calcium and phosphorus digestibility

Blavi, L., and H. H. Stein. 2017. Zinc oxide and microbial phytase may reduce calcium and phosphorus digestibility. National Hog Farmer, Online edition, March 30, 2017. Link to full text.

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Basal endogenous loss, standardized total tract digestibility of calcium in calcium carbonate, and retention of calcium in gestating sows change during gestation, but microbial phytase reduces basal endogenous loss of calcium

Lee, Su A, L. Vanessa Lagos, Carrie L. Walk, and Hans H. Stein. 2019. Basal endogenous loss, standardized total tract digestibility of calcium in calcium carbonate, and retention of calcium in gestating sows change during gestation, but microbial phytase reduces basal endogenous loss of calcium. J. Anim. Sci. 2019.97:1712–1721. Link to full text.

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Effects of microbial phytase on mucin synthesis, gastric protein hydrolysis, and degradation of phytate along the gastrointestinal tract of growing pigs

Mesina Von G. R., L. Vanessa Lagos, Rommel C. Sulabo, Carrie L. Walk, and Hans H. Stein. 2019. Effects of microbial phytase on mucin synthesis, gastric protein hydrolysis, and degradation of phytate along the gastrointestinal tract of growing pigs. J. Anim. Sci. 2019.97:756–767. Link to full text.

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Increasing levels of microbial phytase increases the digestibility of energy and minerals in diets fed to pigs

Arredondo Mónica A., Gloria A. Casas, Hans H. Stein. 2019. Increasing levels of microbial phytase increases the digestibility of energy and minerals in diets fed to pigs. Anim. Feed Sci. Technol. 248: 27 - 36. Link to full text.

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Effects of increasing concentrations of an Escherichia coli phytase on the apparent ileal digestibility of amino acids and the apparent total tract digestibility of energy and nutrients in corn-soybean meal diets fed to growing pigs

Yue She, J. Chris Sparks, and Hans H. Stein. 2018. Effects of increasing concentrations of an Escherichia coli phytase on the apparent ileal digestibility of amino acids and the apparent total tract digestibility of energy and nutrients in corn-soybean meal diets fed to growing pigs. J. Anim. Sci. 96:2804–2816.

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The level of feed intake does not influence digestibility of calcium and phosphorus in diets fed to gestating sows, but gestating sows have reduced digestibility of calcium and phosphorus compared with growing gilts

Lee, S. A., G. A. Casas, and H. H. Stein. 2018. The level of feed intake does not influence digestibility of calcium and phosphorus in diets fed to gestating sows, but gestating sows have reduced digestibility of calcium and phosphorus compared with growing gilts. Can. J. Anim. Sci. 98:591-594. Link to abstract

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Effects of a novel phytase on growth performance, bone measurements, and Ca and P digestibility in diets fed to growing pigs

Blavi, L., J. N. Broomhead, and H. H. Stein. 2018. Effects of a novel phytase on growth performance, bone measurements, and Ca and P digestibility in diets fed to growing pigs. J. Anim. Sci. 96(Suppl. 2):163 (Abstr.) Link to abstract (.pdf)

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Comparison between a novel phytase and a commercial phytase on growth performance and bone measurements in diets fed to growing pigs

Munoz Alfonso, C. J., L. Blavi, J. N. Broomhead, and H. H. Stein. 2018. Comparison between a novel phytase and a commercial phytase on growth performance and bone measurements in diets fed to growing pigs. J. Anim. Sci. 96(Suppl. 2):147-148 (Abstr.) Link to abstract (.pdf)

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Effects of GraINzyme and AxtraPhy phytases in restoring performance and bone ash in pigs fed low-phosphorus and calcium diets

Last month's newsletter included a research report on research into a novel E. coli phytase expressed in corn, called GraINzyme. Results of that research indicated that adding GraINzyme phytase to diets fed to young growing pigs increased growth performance, digestibility of calcium and phosphorus, and bone mineralization. The comparative effects of GraINzyme and a commercial phytase was not tested in the previous study. Therefore, an experiment was conducted to compare effects of addition of GraINzyme phytase to the commercial phytase AxtraPhy in diets fed to growing pigs.

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Effect on growth performance and bone mineralization of GraINzyme phytase in diets fed to growing pigs

Most of the phosphorus in corn and other plant-based feed ingredients fed to pigs is bound to phytate. Pigs do not secrete phytase in adequate quantities to liberate significant amounts of phytate-bound phosphorus, meaning that most of the phosphorus in these ingredients is not biologically available. Calcium digestibility is also negatively affected by the presence of phytate in feed ingredients. One way for producers to ensure that pigs' requirements are met is to add supplementary phosphorus to diets. However, this adds to the cost of diets. The excretion of phytate-bound phosphorus also may contribute to algae overgrowth in waterways.

Another approach is to add supplemental phytase to the diets, to allow pigs to better utilize the phosphorus present in the ingredients. Phytases can be obtained from plants, animals, or microorganisms (bacteria, yeasts, and fungi).

GraINzyme is a source of phytase produced by genetically modified corn plants with genes derived from E. coli. In this experiment, the effect on growth performance, apparent total tract digestibility (ATTD) of calcium and phosphorus, and bone mineralization of adding GraINzyme to weanling pig diets was tested.

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