Not all phytases are the same
- To generate accurate and dependable matrix values, AB Vista utilizes a large trial database to create a holo-analysis.
- A built-in safety margin is also incorporated by using confidence limits, thereby effectively delivering the recommended release of nutrients 9 times out of 10 rather than average release.
Phytase is commonplace in most swine diets today globally. Given the current situation with high feed costs and low pig prices, however, it is a good time to explore taking further advantage of the benefits of phytase, including the use of higher levels of phytase to degrade phytate and lower phytate esters, and ultimately providing an economic benefit to production through lower feed costs or improved animal growth.
In this article, AB Vista aims to highlight key benefits of using phytase in pigs.
Increasing the availability of calcium and phosphorus from the diet
It is well-established that phytase can be used in the diet to release macro-minerals bound to phytate, particularly calcium and phosphorus. Furthermore, increasing the level of dietary phytase may be an opportunity to achieve greater effects on those minerals (Mesina et al., 2019), assuming adequate dietary phytate levels.
In the current market, there is the ability to target greater mineral release with higher levels of phytase. As an example, moving from 500 to 1,000 FTU/kg Quantum Blue would increase avP release from 0.15 to 0.195%, saving $1.50 to $1.75 per treated ton (dependent on the dietary nutrient specification and dietary phytate levels) by reducing the level of inorganic phosphate.
Phytate: the antinutrient
It is important to realize that phytate contains six phosphate groups (IP6 to IP1). Degradation of phytate occurs sequentially with IP6 being reduced easily to IP5 using lower doses of phytase (250 to 500 FTU/kg). Breakdown of the lower esters, particularly IP4 and IP3, may become rate-limiting for many phytases. This transformation of phytate (IP6) into lower esters reduces the anti-nutrient effect of phytate targeting 90% of phytate and lower ester destruction, and consequently, increases the nutrient release. Therefore, phytases are largely differentiated in their ability to destroy 90% of phytate to IP1. Quantum Blue consistently excels at hydrolyzing phytate esters to IP1, and ultimately through endogenous alkaline phosphatases the release of inositol (Fig. 1).
Ref: Mesina et al., 2019
Amino acid release values
Mucin coats the epithelial layer, providing a protective barrier to exclude pathogens and other molecules. It is particularly rich in amino acids such as threonine, aspartic acid, serine and glutamate, but also contains other amino acids (Lien et al., 1997). The presence of phytate increases the production of mucin in pigs and, likewise, more endogenous losses occur as the mucin protects the intestines (Morel et al., 2003). Adding exogenous phytase hydrolyzes the phytate molecule. Less endogenous losses of amino acids are observed with the addition of phytase (Cowieson et al., 2004) and this can be attributed to less mucin being produced and subsequently eliminated (Mesina et al., 2019; Cowieson et al., 2007). Additionally, phytate interacts with dietary protein and amino acids, leaving them largely unavailable to the animal without the addition of exogenous phytase.
As an example, in an early finisher diet a swine production company could take advantage of an amino acid matrix. By moving towards more complete phytate destruction, more amino acids will be released and available for absorption by the animal. If the current nutritional program utilized 500 FTU/kg, the nutritionist could explore moving to higher levels such as 1,000, 1,500, or even 2,000 FTU/kg of phytase to take advantage of a higher amino acid matrix, saving a considerable amount of money, which can be especially valuable in the current market (approximate potential savings of $4.00 to $5.00 per tonne; diet dependent).
Improved nursery pig performance
In the nursery program, many nutritionists take advantage of the traditional “superdosing strategy,” whereby the release of the nutrients from phytate are used to support additional growth rather than using matrix values for energy and amino acids in the nursery via the inclusion of higher levels of phytase (2,000 FTU/kg or greater). Internal data on 50+ studies have shown that superdosing phytase (AB Vista internal data) improves nursery performance by 8% in ADG and 5% in FCR. This can be attributed to phytate and lower phytate ester breakdowns that improve mineral, amino acid and energy utilization, but may also be supported by the release of inositol and the reduction of gastric pH.
The addition of exogenous phytase degrades the phytate to lower esters and ultimately inositol (Mesina et al., 2019). Some have focused solely on the reduction of IP6; however, it’s clear that the lower esters are equally problematic to the pig. Thus, complete destruction of phytate should be the goal to support optimal piglet performance. Beyond the destruction of phytate, the inositol molecule itself is advantageous. Inositol plays a key role in metabolic function, cell growth and nervous system development. Supplementing pure inositol is not an economical option for producers; however, superdosing phytase is a feasible alternative to supply the inositol through phytate degradation. In a commercial study, the addition of 2,500 FTU/kg of phytase was able to match the performance of piglets fed the highest level of inositol (Moran et al., 2019) and the authors identified inositol as a potential semi-essential nutrient in the young animal.
It has been observed that nursery pigs cannot secrete the HCl necessary to lower pH for pepsin to effectively digest proteins, which can ultimately limit nutrient utilization. An increased gastric pH can also be attributed to the inclusion of ingredients with a high acid-binding capacity, such as limestone and monocalcium phosphate. If passed through to the large intestine, undigested proteins can be fermented to toxic compounds that can promote post-weaning diarrhea. In a recent trial evaluating superdosing levels of phytase in nursery piglets, the investigators were able to capture the real-time gastric pH using a capsule (Figure 2). It was evident that when higher levels of phytase were fed, more time was spent at lower pH ranges. Aligned with this finding, pigs have also shown reduction in post-weaning diarrhea (Moran et al., 2017 and Lagos et al., 2021).
Improved performance helps drive down cost/kg of gain and can translate into a $0.40 to $0.60 per pig savings for the same amount of nursery gain. This does not factor in the benefits that lower post-weaning diarrhea may have in terms of pig fallouts and medication usage.
Reference: Lee et al., 2021
Reduced farrowing time in sows
It has been previously observed that sows fed superdosing levels (≥2,000 FTU/kg) of phytase during lactation had reduced stillborns. Therefore, a university research trial was designed to evaluate potential mechanisms as to why superdosing phytase would elicit that response. In this study, superdosing phytase tended to reduce the number of stillborn piglets (Manu et al., 2018; Table 1). This reduction in stillborn piglets was associated with a reduced (P < 0.05) farrowing duration. Overall piglet pre-weaning mortality was 18.3% in the control group and 15.0% in sows fed 2,500 FTU/kg Quantum Blue. It was hypothesized that this response was due in part to the degradation of phytate, releasing calcium to be used for muscle contraction. The researchers also hypothesized that this was related to IP3 and its involvement with signaling oxytocin
Conclusion
There are numerous benefits of adding a proven phytase to the diet, with some outlined in this article. It is important to recognize that even if the dietary formulation is not crediting the phytase, it is still providing several key benefits. Even when those benefits are not credited, phytase will supply additional growth performance rather than saving costs at the diet level.
Selecting a phytase that not only targets phytate (IP6) breakdown but also the lower phytate esters is key. Quantum Blue is based on a robust dataset, with confidence limits built into the matrix to ensure a consistent nutrient release is achieved.
