High-dose phytase used with a high dose matrix can reduce the cost of feed; however, the purpose of super-dosing phytase is to improve animal performance.

The use of high doses of phytase relatively reduces the cost of high phytase due to the reduction in the amount of inorganic phosphorus added to the feed (for example, mono calcium phosphate or mono dicalcium phosphate) due to the highest release of organic phosphorus compared to conventional phytase dose.

The existing interest in the use of high levels of phytase is driven by the supply-demand effect in the market. That is, the decrease in production and the increase in the demand for mono calcium phosphate in the fertilizer sector have constantly fueled price increases. This trend is expected to go on.

Super dose phytase administration may be an appropriate option for a poultry breeder who aims to increase his total profit by increasing animal performance under certain conditions. This comes into play when the increase in feed costs due to the increase in phytase used is offset by the additional gain from the increase in performance.

As we all know, phytate is the main storage form of phosphate in plants. This phosphate is in the form of myo-inositol-hexa phosphate (IP6). When phytase comes into contact with phytate, it forms myo-inositol-penta phosphate (IP5) and a phosphate molecule is released. The reaction proceeds so that IP4, IP3 and IP2 are formed. The product of the phytase molecule reaction is IP1, and in this process, 5 phosphorus molecules are released.

Although exogenous phytase cannot degrade IP1, the intestinal mucosa produces alkaline phosphatase that degrades this IP1. As a result of this process, inositol and six molecules of phosphorus are released as the final product. In addition, according to documented studies, when phytase is added to the diet, not only phosphorus is released, but also the presence of calcium, energy and amino acids increases.

WHAT EXACTLY IS A SUPER DOSE ADMINISTRATION?

Super-dose is to administer the phytase at a dose beyond the matrix boundary dose. For example, if phytase is administered at a dose of 1,500 FTU and a matrix of 1,000 FTU is used, this indicates that either feed conversion (FC) or body weight (LW) increase is targeted. This should not be confused with the concept of high dose, where the matrix is administered according to the same dose.

When using a super-dose, the efficacy and amount of phytase (to prevent myo-inositol production and the production of phytate esters, namely IP5, IP4 and IP3, in the intestines) must be at a sufficient level to degrade high levels of phytase.

EFFECTS OF SUPER DOSE ADMINISTRATION

A lot of research has been published on super dose administration. These articles mention various possible mechanisms of action. Among them are a higher degradation of phytate resulting in higher levels of calcium and phosphorus release and a 1:1 calcium/phosphorus ratio. Another example is that phytate affects protein digestion by reducing pepsin activity.

We know that phytate irritates the intestines, and by degrading phytate and its esters, intestinal mucosal irritation will be reduced. The addition of phytase increases the availability of threonine, cystine, glycine and serine amino acids. These amino acids are the main components of mucin secreted from the digestive tract.

One of the most discussed mechanisms of action of super-dose administration is increased myo-inositol production and absorption (Kreseldi et al., 2021). It has also been proven that super dose administration reduces enteritis due to phytate degradation.

POINTS TO CONSIDER IN SUPER-DOSE ADMINISTRATION

It is important to consider factors such as feed structure, feed digestibility, feed composition and efficacy, and the use of a proven phytase. The density of the feed composition is also important, as super-dosing will only be effective if the feed has sufficient energy and amino acids in order to promote positive effects on performance.

According to the studies conducted by Cargill, the phytate level in the feed and the source of the phytate should be considered, as their interactions with phytase will be different depending on the raw materials in the feed.

Phytate is a substrate for phytase but is sometimes a factor limiting phytase's action.

FOLLOW THE SCIENCE

Considering the effect of super dose administration on animal performance, in various studies, we witness that phytase doses above 1,000 FTU have a positive effect on body weight gain and feed conversion. Although not all studies demonstrated a significant positive effect, there is a clear trend revealing that the use of higher doses of phytase increases FC and LW.

For example, a study (2020) conducted by Cargill at the Federal University of Viçosa showed that increasing the dose of phytase in feed causes a linear increase in FC on days 0-42. In this study, a positive control (PC), a negative control (NC) with reduced calcium and phosphorus levels, and a second negative control (NC2) with also reduced amino acid and energy levels have been established.

As phosphorus supplies decrease and prices increase, super-dosing under the proper conditions will become an option for poultry breeders. Complete degradation of phytate, availability of essential nutrients, reduced production of phytate esters, and production of myo-inositol may all contribute, to a different extent, to the beneficial effects of super-dosing.

It is also important to consider all factors, such as the structure and composition of the feed, as well as the administration of a proven safe phytase.