BASF: Interplay between phytase supplementation, diet acidification and dietary calcium (Ca) level in broilers

Monday, October 4, 2021


BASF: Interplay between phytase supplementation, diet acidification and dietary calcium (Ca) level in broilers


Dr. Yauheni Shastak and Dr. Dieter Feuerstein, BASF SE, Germany

 


Exogenous phytase is the most common enzyme in the feeding of non-ruminants. The world's first commercial phytase, Natuphos, capable of breaking down phytate, was introduced in the Netherlands in 1991. Today, the global phytase market is valued at around 450 million US dollars. By 2025, it could reach 600 million US dollars.


Unlike some other enzymes, the feasibility of using phytase in diets of monogastric animals and poultry is proven and undeniable. Thousands of scientific publications confirm the high efficacy of this enzyme in various diets since most of the phosphorus (P) in plant feed components is in the form of phytate (InsP6) - salts of phytic acid. However, phytate P is only partially utilized in pigs and poultry due to several reasons. Thus, inorganic feed phosphates and phytase enzyme (which breaks down phytate) are included in plant-based diets to cover animals P requirement.


Phytate degradation in the digestive tract depends on several factors. Diet acidification as well as dietary Ca level are known influences on the P utilization in broiler chickens. A recent study conducted by the Institute of Animal Science of University of Hohenheim (Krieg et al., 2021) investigated interplay between hybrid 6-phytase supplementation (Natuphos E), diet acidification and dietary Ca level in broilers. A 3 × 2 × 2 factorial design for the experiment with two Ca levels (5.6 and 8.2 g/kg dry matter) and two phytase supplementation levels (0 and 1500 FTU/kg) was used. The third factor was the addition of 6 g formic acid/kg to limestone-containing diets or replacing limestone by Ca-formate. Phytate-P degradation as well as P digestibility was measured at the ileal level. Phytase supplementation increased ileal phytate degradation (P < 0.001) to approximately 80%, irrespective of the dietary Ca level. Without phytase supplementation, ileal phytate degradation was 9 points higher for the low compared to the high Ca level (P < 0.001) (Figure 1). Interestingly, Ca level had no effect on ileal phytate degradation for treatment limestone + formic acid, yet the high Ca level decreased ileal phytate degradation by 4 points for limestone (P < 0.05) and by 10 points for Ca-formate (P < 0.05) (Figure 2). Increasing dietary Ca decreased ileal P digestibility which is a well-known scientific fact. However, this effect was more pronounced for Ca-formate, with 12 points (P < 0.001), than for limestone and limestone + formic acid, with 7 points each (P < 0.001) (Figure 3). The three-way interaction was not significant for either ileal phytate degradation or P digestibility (P > 0.05).

 

Figure 1:  Phytate P degradation at the level of ileum in broilers fed with low and high Ca levels. Columns within a statistical comparison not sharing the same letter are significantly different (P ≤ 0.050).
 


Figure 2:  Phytate P degradation at the level of ileum in broilers fed with differently acidified diets with low and high Ca levels. Columns within a statistical comparison not sharing the same letter are significantly different (P ≤ 0.050).

 

Figure 3:  Ileal P digestibility in broilers fed with differently acidified diets with low and high Ca levels without and with supplementation of 1500 FTU phytase/kg. Columns within a statistical comparison not sharing the same letter are significantly different (P ≤ 0.050).


Phytate being a salt of an acid implies an ionization step at low pH to be solubilized and become accessible for phytase action. Inclusion of acidifiers into broiler diets may help to improve phytate solubilization and thereby enhance phytate degradation by supplemental phytase in the proximal part of digestive tract. Furthermore, Ca is the major cation in broiler diets and is involved in complexation of phytate in the gut inhibiting phytate hydrolysis by phytases. The results of the above-mentioned study clearly show that high dietary Ca levels reduced ileal phytate degradation, yet this effect was compensated by phytase supplementation. Surprisingly, if no phytase was added, inclusion of more soluble Ca source such as Ca-formate led to significantly lower levels of ileal phytate degradation and P digestibility compared to supplementation of Ca in form of limestone or separate addition of limestone+formic acid. Therefore, solubility of different Ca sources may be of relevance in phytase action in the digestive tract.


Concluding remarks


Effects of Ca on phytate degradation and ileal P digestibility seem to depend on dietary concentration, solubility of the Ca sources, as well as on the consequences of Ca supply on the pH of the gastro-intestinal tract. The results of this study are of importance to the industry since choice of concentration and source of Ca in the diet is a crucial factor of feed formulation that influences P utilization by the birds.

 

 

For more of the article, please click here.


Article made possible through the contribution of Dr. Yauheni Shastak, Dr. Dieter Feuerstein and BASF SE, Germany

Video >
Technical Paper >
Subscribe Technical Forum eNewsletter
Please input your name.
Please input your company name.
Please input a valid email address.
Please input your job title.
Please select your business category.
By clicking Submit, I am agreeing to receive eFeedLink eNewsletter and understand that the information I've provided here will be saved by eFeedLink. eFeedLink guarantees that your details will not be shared with any third parties.