Modern Phytases like AXTRA PHY GOLD can increase ileal Digestible Energy by over 1 MJ/kg

Dr David Cadogan – Feedworks Monogastric Technical Services

Over 15 years ago, research on first and second-generation fungal and E.coli phytases showed inconsistent effects on the digestibility of ileal and faecal (gross) energy in growing pigs. While some studies reported significant improvements in energy and fat digestibility, other studies showed no to very small increases in energy availability.

Modern phytases developed over the past 3-4 years have a substantially higher ability to breakdown phytic acid in the upper GI tract, therefore reducing phytates ability to chelate/bind to nutrients, reduced anti-nutritional effects and aggravation of the gut and small intestine.

The new generation Axtra PHY GOLD phytase was developed using CRISPR technology to produce a very high rate of phytate hydrolysis, enabling the enzyme to withstand very low pH and endogenous protease breakdown. While the Axtra PHY GOLD can improve phosphorus by 2-fold, calcium by 30-40% and amino acids by over 6% (Espinosa et al, 2022; from Hans Stein™s group Illinois State University), the recent improvements in ileal digestibility have been extremely high (Table 1).

Table 1   Published increases in ileal (gross) energy digestibility by AXTRA PHY GOLD from pigs between 25 and 50 kg live weight

Journal Paper Axtra Phy dose rate % improvement GE Ileal DE increase
Espinosa et al 2022 1000 FTU/kg   8.7% 1.14 MJ/kg
Velayudhan et al 2023 1000 FTU/kg average   4.0% 0.61 MJ/kg
Cadogan et al 2023 1270 FTU/kg 11.1% 1.36 MJ/kg
Average   7.9% 1.04 MJ/kg


The reasons for the increased energy digestibility are likely to be a combination of improved protein starch and fat digestibility/absorption, reduced endogenous excretions and improved endogenous enzyme activity.

With the cost of 1 MJ/kg of digestible  energy in 2023 well over $50/tonne for grower diets and approximately $35 per MJ in finisher/withdrawal diets, the energy uplift by new generation phytases have a large potential to reduce the cost of pork production in the future.



ESPINOSA C.D., TORRES L.J., VELAYUDHAN D.E.,  DERSJANT-LI Y. AND STEIN H.H. (2023). Journal of Animal Science. 100, 1-8.

CADOGAN D.J., WILKINSON S., VELAYUDHAN D.E., DERSJANT-LI Y. AND COTTRELL J (2023). Animal Production Science, in press.

VELAYUDHAN D.E., VINYATA E, HARDY R., MARCHAL L., NYACHOTI M., STEIN H.H. AND DERSJANT-LI Y.(2023). Journal of Animal Science. 101, Supplement 1.