NUTRITION ▶▶▶


Table 2 – Factors Effecting Accessibility of Phytate to Phytase. Positive factors influencing the


accessibility of phytate • Water pH <6


• Water temperature <20° C


• Dietary calcium <0.9% • Phytate: protein ratio <0.04:1


• Dietary chloride concentration > 0.25% • Presence of protease & carbohydrases • Most phytate come from cereals & grain legumes, little from by-products • Presence of acidifiers


• No therapeutic use of Zn or Cu • Low viscosity cereals


Negative factors influencing the accessibility of phytate • Water pH >8


• Water temperature >30° C • Phytate: protein ratio 0.05:1


• Dietary chloride concentration <0.25% • No protease or carbohydrase use


• Substantial concentration of phytate from by-products such as rice bran • No acidifiers in the diet or water • High concentrations of Zn or Cu • Highly viscous cereals


materials and finished feed. This method uses the near-infra- red region of the electromagnetic spectrum to determine the quantity of specific molecules present in a material. DSM has tested many thousands of feed and raw material samples, using both NIR and wet chemistry methods. This has enabled the company to devise a robust phytate-P NIR equation for ingredients and complete feed. This allows rapid and cheap measurement of the amount of Phytate-P in a giv- en sample. Such a dynamic analytical tool combined with an accurate prediction model may be the ideal solution for opti- mum phytase dosing. By knowing the level of phytate-P in the feed, it becomes easy to determine the most effective phytase dose to add to the feed. Figure 2 shows the relationship between phytate-P measured, phosphorus release and the dose of phytase needed to achieve this level of phosphorus re- lease. On the X axis we have Phytate-P concentration as meas- ured in feed, and the Y axis shows the amount of available


Figure 2: The phytate-phytase nutrient space in practical diets. 0.25


Zone 1 0.2 0.15 0.1 Zone 2 0.05 0 Phytate-P (%) 22 ▶ POULTRY WORLD | No. 2, 2021 Zone 3


3000 FYT/kg 2500 FYT/kg 2000 FYT/kg


1500 FYT/kg 1000 FYT/kg


500 FYT/kg


Careful alignment Intelligent Phytase Nutrition is the DSM system of precision phytase dosing. For accurate phytase dosing, first the amount of substrate (phytate) in the diet is determined. With this value in mind, the most efficient level of phytase supplemen- tation is then calculated to remove as much of the phytate as possible. This careful alignment of dose and substrate not only optimises the phytase investment but also maximises the precision with which feed raw materials are used, thereby improving animal production efficiency and reducing the environmental footprint.


References available upon request


phosphorus that you want to release with your phytase. This graph can then be subdivided into three distinct zones. • Zone 1 (Phytate-P limiting) – Low Phytate-P in the diet: high phytase levels are unnecessary because the substrate is limiting, adding more phytase will not release more phosphorus. You need to be careful as you may be overes- timating how much phosphorus you are releasing with your phytase.


• Zone 2 (Phytate-P not limiting) – Perfect balance between Phytate-P and phytase dose.


• Zone 3 (Phytate-P in excess) – High Phytate-P concentra- tions; higher levels of phytase will release more phospho- rus. The limiting factor in this case is phytase concentration.


Benefits for all By accounting for variable dietary phytate levels, nutritionists can achieve a better balance between phytase dosing and phytate level, thus destroying as much of the anti-nutrient as possible at minimum cost. This Intelligent Phytase Dosing benefits producers, birds and the environment. Flock perfor- mance, uniformity and feed costs are improved. Improved gut health will also be seen, leading to better litter quality, improved bird welfare and greater skeletal integrity. For the sustainability of the industry and compliance with local pol- lution and welfare restrictions, less nitrogen and phosphorus will be excreted, thus benefitting the environment.


Fine tuning – accessibility of phytate to phytase In the model described above, phytate accessibility is as- sumed to be 80%. This is an excellent estimate for modern phytases but can vary based on many factors, such as calcium level and source, choice of raw material, the use of acidifiers and even the presence of other enzymes. Table 2 shows the main interacting factors which can either increase or de- crease phytate accessibility. DSM has taken all the latest infor- mation on these factors into account and developed a model to predict their impact, so that nutritionists can optimise phytase dosing even further.


Available P release (%)


0


0.025 0.05


0.075 0.1


0.125 0.15


0.175 0.2


0.225 0.25


0.275 0.3


0.325 0.35


0.375 0.4


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