What should you know when choosing the right phytase for your diet
Regional Technical Sales Manager, Danisco Animal Nutrition & Health (IFF)
1. What are the characteristics of the ideal phytase?
Phytate is a problem because its phosphorus is indigestible to monogastric animals and it has strong anti-nutrient effects. In the upper digestive tract, at low pH, phytate binds to proteins and amino acids. Further down the digestive tract, at higher pH levels, phytate binds to minerals such as calcium and trace elements. As a result, precious nutrients in the feed are not absorbed by the animal and bodyweight gain and feed efficiency are reduced. Phytate’s interference with digestion also stimulates the animal to increase its production of endogenous secretions, an energy and nutrient consuming process, leading to reduced animal performance.
Therefore, the ideal phytase needs to break down phytate as quickly as possible to reduce its negative impact. This requires an enzyme that is highly active at low pH in the bird’s upper digestive tract. This positive mode of action will enable the phytase to prevent phytate stimulating the production of endogenous secretions and help to avoid potential environmental problems caused by the excretion of unabsorbed phosphorous and nitrogen. These measurable benefits make it more important than ever that the most effective phytase, developed using the latest enzyme technology, is part of your nutritional feed strategy.
2. What are the extra-phosphoric effects of phytases?
It is well accepted that phytase liberates phosphorous and can replace inorganic phosphate. However, recent efforts to maximize phytase applications have shown that the effects of phytase go beyond phosphorous release. These so called extra-phosphoric effects work to increase the availability of amino acids, energy and minerals, which all drive improvements in growth performance as well as feed efficiency. These developments have led to growing awareness among nutritionists that the traditional phytase dosing recommendation of 500 FTU/kg is insufficient. Rather than taking a blanket approach, every poultry producer has different requirements for optimizing animal performance and needs a tailored phytase dosing approach based on life stage and specific feeding program. It’s an area that demands significant and continuous investment in order to achieve success, which is why Danisco Animal Nutrition remains at the forefront of phytase research and innovation; generating the species, life stage and diet-specific data that nutritionists need to make smart decisions. Maximizing extra-phosphoric effects also has wider benefits for the environment. By driving greater use of phytase in a diet and application manner, it is reducing the global use of inorganic phosphate and will ultimately lead to lower environmental pollution per unit of production.
3. Do specific raw materials have an impact on phytase activity?
Not all phytate is created equal and phytate accessibility and thus digestibility seems to differ between raw materials. This is a topic of continuing research and we look forward to bringing new application knowledge in this area to our customers in the future. The practical consequence of these differences in digestibility is that adjustments of phytase contribution values based on the phytate level in the diet should be based on a large data set gathered from diverse diets covering a wide range of phytate levels, instead of some gross approximation based on handful of data points.This is precisely why we have invested in running many digestibility and performance trials for both matrix generation and validation of Axtra PHY GOLD.
4. Can I formulate diets with phytate-rich raw materials when using Axtra® PHY GOLD?
Our research has shown that in addition to demonstrating that the full removal of inorganic P from day one is possible without compromising growth performance (see Q1), using Axtra ® PHY GOLD may also facilitate greater flexibility in terms of raw materials – including those rich in phytate. In fact, trials suggest that it could offer the opportunity to move to higher phytate levels in young chick diets and potentially relax constraints on the addition of phytate-rich ingredients in starter diets.
Reduced feed costs per kg bodyweight gain (BWG) and improved profitability were also reported for all IPF treatments, with the greatest economic returns achieved with a phased dosing strategy.
These preliminary results are a welcome development for producers who are increasingly likely to have to change feed formulations due to global uncertainty around raw material imports. Using more locally sourced ingredients might lead to increased phytate levels in the diet which in itself is an opportunity for Inorganic Phosphate Free diets. So having initial data to support the benefits of using a reliable, well researched phytase, such as Axtra® PHY GOLD, as part of a tailored dosing strategy, means you can be confident to make needed variations to your feed formulations.
5. What animal-related factors affect phytase activity?
A wide range of factors need to be taken into account when choosing a phytase dose. Animal age, general and gastrointestinal system, immune function, physiological state, growth trajectory, stress levels, as well as differences in available diets and feeding strategy all have a role to play. In young animals, for example, higher dietary phytate levels are typically seen due to the inclusion of high-protein meals, so a quick removal of phytate can result in strong performance benefits. On the other hand, older animals may also benefit from a high phytase dose if specific inclusions are added to the feed, such as high phytate and fibre ingredients, calcium and/or other nutrients. As each situation is different, we believe that the only way nutritionists can meet individual needs is through a tailored dosing approach based on species, life stage and diet. Most importantly, this optimized dose needs to be based on proven science.
6. What does superior pH profile mean for animal performance?
A phytase with a superior pH profile is highly active at low pH which means it starts to break down phytate in the acidic part of the digestive tract; before it enters the small intestine. With a superior pH profile, Axtra® PHY GOLD is the most bioefficacious phytase enzyme currently available on the market. Its superior pH profile means it works faster than any other competitor phytase to break down phytate, which would otherwise interfere with digestion and performance. As a result, Axtra® PHY GOLD can improve the release and subsequent uptake of phosphorous, calcium, energy and amino acids, reduce the anti-nutritional effects of phytate, and deliver greater feed cost savings.
7. What is the correlation between the in vivo and in vitro performance of phytase enzymes?
The mode of action of phytase is unique among feed enzymes. Laboratory tests can predict animal performance through pH profile, phytate degradation and protein-phytate complex degradation. Some of these tests can be easily visualised as we demonstrated in our video “the miracle of phytase”. Animal trials however are crucial to validate animal performance and to develop credible matrix values that are species, life stage and diet specific.
8. How do I optimize phytase dosing, based on my specific diets and animal growth stage?
Every diet needs to be evaluated for optimum phytase inclusion levels, so we have to find the dosing level that works for each situation in order to provide the best enzyme and substrate ratio – and so optimize phytase use. That’s why we offer specific recommendations linked to the dietary composition, phytate levels, limestone solubility and individual customer needs. We also advise that full digestibility matrix values for P, Ca, metabolizable energy and amino acids are applied to maximize production benefits. Of course, changes to the physiological state of the animal also need to be considered. Factors such as growth trajectory, age, environmental and health challenges, as well as production systems all have an influence on nutrient requirements, meaning optimal ratios may need to be adjusted accordingly.
9. How do I get the Ca/P balance right?
Calcium (Ca) is essential for bone development and a key player in several metabolic pathways. Given its importance and relatively low cost, it is often added to diets with large safety margins to avoid deficiencies. However, limestone is also often used as a flow agent or carrier within other ingredients, such as soybean meal, so often goes unaccounted for. This means you can end up with a higher concentration of calcium in the diet than expected, which can negatively affect the activity of phytase and the availability of phosphorous. So too can the calcium source which can vary in terms of particle size, solubility, and mineral content. Consequently, although calcium deficit certainly poses a threat to animal growth, over-supplementation can also severely impair productivity. This is due to increased calcium phytate binding in the early gut which may also lead to reduced protein digestibility. Which means dietary calcium is very much a double-edged sword. However, its antinutritional effects can be overcome with the right phytase dosing strategy.
A fast-acting phytase with superior pH profile, such as Axtra ® PHY GOLD, is essential. This is because calcium binds phytate more easily with increasing pH, so the phytase enzyme needs to be highly active at low pH in order to increase phytate hydrolysis in the acid environment of the gut; before it enters the small intestine. It can then quickly release phosphorous for absorption and reduce the formation of insoluble calcium-phytate complexes. In all cases, achieving the optimal Ca/P balance for maximum animal growth requires a customized supplementation strategy of both calcium source and phytase.
10. Can I completely replace phosphorous supplementation in my diets without compromising animal performance using exogenous phytase enzymes?
Yes, our research at Texas A&M University shows that this is now a viable option. Trials have demonstrated that our highly bioefficacious phytase enzyme, Axtra® PHY GOLD, can successfully replace inorganic phosphorous supplementation from day one in all vegetable diets while maintaining bone mineralization for broilers, piglets and fattening pigs as long as there is sufficientphytate in the diets. Maintaining bone mineralization is crucial given longstanding concerns that Inorganic Phosphate Free diets can potentially result in lameness and raise welfare issues; so the finding effectively removes one of the main barriers to its adoption. Beyond this groundbreaking study, wider research continues to build a strong case for Inorganic Phosphate Free diets – both in terms of animal performance and cost savings. We are now running application trials under commercial conditions looking into relaxing constraints on inclusion of phytate rich ingredients, and freeing broiler diets from the burden of inorganic phosphate supplementation – and we fully expect Axtra® PHY GOLD to remain at the forefront of more sustainable developments in broiler and swine production.
11. Do I need to consider any other factors if I completely remove inorganic phosphorous from my diets?
It is essential to ensure that there is sufficient phytate phosphorous (P) in the diet to meet the requirements of the birds combined with a proper phytase dosing strategy to release the required phosphorus. Get it right and the benefits can be far-reaching. While the initial studies at Texas A&M University used relatively high phytate levels of 0.33% ongoing work shows that less phytate can be sufficient to maintain performance – particularly in finisher-phases. This not only leads to further reductions in P excretion but, in combination with the application of amino acids and energy matrix values for the phytase, could also reduce nitrogen excretion. Additional research is also ongoing among commercial flocks to further validate the full removal of inorganic P in a wider range of diet types and at a larger scale – and initial results are equally positive. This is all part of an industry-wide drive to ultimately reduce the use of monocalcium-phosphate in broiler feeds by at least one million tonnes per year. A goal that represents a massive step towards more environmentally sustainable broiler production and a significant decrease in the poultry industry’s impact on the pollution of local streams and rivers through runoff.
12. Why do you continue to invest in the development and validation of matrix values?
Nutritionists are constantly looking for scientifically proven matrix values, based on a large number of animal trials, to maximize their phytase application while also reducing feed costs. As phytase is included in essentially all compounded poultry and swine feed globally, we believe all new feed additives should be tested in diets containing an optimized dose of phytase. In many situations, one plus one does not always equal two, and sometimes there are synergistic effects that can be capitalized on. It’s also important for customers to look closely at how matrix values are determined, for example: What methods are used? What data is there to support the recommendations?
Our matrix values for combinations of feed additives are continuously evaluated and validated. Our Animal Nutrition Applications & Technical Service laboratories in China and India also allow us to respond with sophisticated solutions to the dynamic market conditions and customer needs. This, together with our investment in ongoing research and animal trials, generates the necessary knowledge to support more customized recommendations for phytase application. Crucially, it enables us to provide the species, life stage and diet specific data that nutritionists need. So, by committing to continuously providing the most up to date information and insights, we help our customers make the right decisions to maximize animal production and profitability.
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