Thermostability is an important characteristic of a phytase. Their ability to withstand the rigors of the pelleting process can have a big impact on efficacy and animal performance.
OptiPhos® Plus is available in two dry forms for use in feed:
A total of 14 pelleting trials in Europe (in five different locations) and six in the USA (in five different locations) have been conducted since 2017 using both product forms. In most of these trials, competitor products were also included to compare the performance of OptiPhos® Plus to commercial standards.
The most frequently used competitor products were a Buttiauxella phytase and an E. coli phytase expressed in Trichoderma reesii with a claim of being intrinsically heat stable. The large number of trial locations provided a variety of pelleting installations, mimicking real situations in the field.
The pelleting parameters of these trials ranged from:
Recoveries were determined in two ways:
Recovery (%) = (phytase in supplemented pellet - phytase in blank pellet) / (phytase in supplemented mash - phytase in blank mash) x 100%
Thermostability means a recovery of at least 80%.
Some competitors put a large amount of phytase overage in their product to meet the required activity level in the final pelleted feed. For instance, a 1,000 FTU/kg pelleted feed can be achieved even when 50% of the initial phytase activity is lost when the phytase product claims 10,000 FTU/g but in fact actually contains 20,000 FTU/g.
All data from the pelleting studies are plotted in Figures 1 and 2, which includes a best fitting curve.
Figure 1. Average recovery of OptiPhos® Plus CT and G versus competitors as determined by real analysed value
Figure 2. Average recovery of OptiPhos® Plus CT and G versus competitors as determined by label claim considering the excess (overage) of phytase in the product
It can be concluded that: