SPONSORED BY AB VISTA
Phytate breakdown products also anti-nutritive
Recent publications have shown that it is not just phytate that has anti-nutritive effects; the breakdown products of phytate - IP5, IP4 and IP3 – can also have an anti-nutritive effect in the animal. These lower phytate esters have been shown to correlate with poor digestion of protein; energy; and minerals, indicating that they have an anti-nutritive effect in the animal. The key point is that, with standard phytase dosing, we may be degrading one anti-nutrient and simply replacing it with another.
Despite this, confusion still exists in the market as to what superdosing is and how this should be defined. Many end-users have now adopted the practise of superdosing, which involves using higher phytase doses in feed to reduce the anti-nutritional effects of phytate (IP6) in pigs and poultry. This has proven to give additional animal performance benefits beyond standard phytase doses.
Ongoing research and customer experience has helped AB Vista go a step further in defining superdosing as; ‘feeding enough of an effective phytase to prevent the build-up of lower phytate esters such as IP3 and IP4 in the gut of the animal’.
When we think about phytases, we should think about them as enzymes to effectively breakdown IP5, IP4, and IP3 as well as IP6. We want phytases not only to release the phosphorus we need, but to eliminate all inhibitors of digestion, and enable the animal to grow more efficiently. Superdosing phytase does exactly that.
In addition, we need to consider what happens when we break down IP3 to IP2 and then IP2 to IP1. Since IP1 is a substrate for the animal’s own endogenous alkaline phosphatases, with these enzymes the animal can take off the last phosphorous from IP1 producing inositol.
Studies by Zyla in 2004 showed that feeding just 1kg of inositol to chickens improved growth rate and FCR just simply by adding 1kg of this material into diets. This suggests that inositol is playing a role as a nutrient that will improve the performance and efficiency of the animal when added at a 1kg per tonne.
Superdosing increases inositol release in the animal
Complete phytate destruction in the digestive tract may lead to increased levels of inositol released in the gizzard, which is then absorbed and results in better body weight gain and improved feed conversion. We believe that inositol provision is probably responsible for approximately 30% of the total response seen from superdosing.This suggests inositol is an essential nutrient that is not supplied adequately in a typical diet.
Important phytase characteristics
Superdosing therefore gets rid of the phytate ester anti-nutrients, and also provides a nutrient – inositol. In order to achieve this, the phytase has to survive high-temperature pelleting in feed production. It also has to survive the conditions of the stomach, which is where phytases work. Most importantly, however, the phytase has to be able to break down IP6, IP5, IP4, IP3 and IP2, all the way down to IP1 very rapidly indeed. This has to be done in a quantitative manner; expelling most of the IP’s, since these are anti-nutrients. But we also have to provide as much IP1 as possible, so that the animal can break that down and produce inositol.
Watch the videos
AB Vista is an animal nutrition technology company that provides innovative products and services to the animal feed industry. We have produced a series of videos which explain the science behind phytase superdosing, and examine the latest research results. ‘Phytase Superdosing – where are the benefits coming from?’ parts one and two can now be viewed at www.abvista.com.
Click here to view the video.