During the development and selection stages, it was often noticed that phytases with higher heat stability had lower performance in feed. The main reason for that is visualised in Figure 1.
- Each phytase has a temperature profile and an optimum temperature where it will perform at its maximum.
- The higher this optimum temperature, the more heat stable the phytase will be. For instance, Phytase 2 in Figure 1 is more heat stable than Phytase 1.
- However, the body temperature of an animal is approximately 40oC, so a higher optimum temperature also means a lower activity at 40oC, requiring a higher dose per kg of feed. For example, Phytase 2 (the more thermostable phytase) needs to be included at a higher dose to equal the performance of Phytase 1 at 40oC (Figure 1).
Increased heat stability combined with improved animal performance was not simple, but we achieved this with OptiPhos® Plus, showing improved matrix values versus current OptiPhos®.
Higher matrix values for OptiPhos® Plus
Biochemical work carried out during the development of OptiPhos® Plus has revealed that OptiPhos® and OptiPhos® Plus have a similar Vmax value (maximum speed of phtyate degradation). However, it was observed that OptiPhos® Plus had a higher affinity to phytate compared to OptiPhos® (Figure 2).
The affinity of a phytase is defined as the Km value, which is the phytate concentration at which the spped of the phytase is 50% of its Vmax (Figure 2). A low Km (high affinity) means that the phytase can keep up its maximal speed for a longer time, even when phytase concentrations are getting low, and so will give higher phosphorus (P) matrix values in vitro.
Validated in animal trials
Many animal studies in broilers and pigs have been conducted to confirm the P matrix value for OptiPhos® Plus at different inclusion levels. The P release response with increasing dose is a logarithmic curve as shown in Figure 3 for broilers and turkeys (available P (aP)) and in Figure 4 for pigs (digestible P (Dig. P)).
Scientifically claimed matrix values
Unlike many of our competitors, the P matrix values for OptiPhos® Plus have been calculated based on all our research data and not just the best trials. This means that the values we state are scientifically supported, reliable, and do not represent an overestimation of the potency of OptiPhos® Plus. Even formulating with low aP or Dig. P targets in the diets, OptiPhos® Plus will deliver correct values. This gives the nutritionist 100% certainty that when calculating with these values, no P deficiency will be observed in the field under any circumstances.
Conclusion
The improved intrinsic heat stability of OptiPhos® Plus does not compromise its performance capabilities. On the contrary, its higher affinity to phytate leads to a higher phytate degradation and by consequence to higher P matrix values.
The matrix values of OptiPhos® Plus are scientifically supported, using all trial data, reliably and consistently delivering P release and optimal animal performance.
