The improved digestibility of phytate-bound phosphorus (P) in feeds by using Ronozyme® HiPhos phytase from DSM Animal Nutrition & Health allows nutritionists to reduce the use of expensive inorganic phosphates resulting in substantial savings on feed costs. Furthermore, phytases play a vital role to support the sustainability of pork production by reducing P in manure.
How Do We Compare Phytases?
Manufacturer’s recommendations vary considerably in terms of units (FTU, FYT, or U/kg diet) to replace a given amount of P. This difference can be attributed to several factors:
● The source of the production enzyme gene impacts several enzyme characteristics, including stability and efficacy.
● Phytase analytical procedures can express the units differently. Differences in buffer, for example, can “reduce” the number of expressed units by 50 percent or more to falsely suggest a phytase is twice as effective. Thus, assayed activity is a poor predictor of in vivo activity across different phytases.
● Another consideration is the survivability of a phytase during the pelleting process. Todays’ phytases are stabilized with a quick-release pH-mediated coating, or by genetically modifying the protein itself. Despite these efforts, not all phytase products perform equally when subjected to the rigors of feed processing or during storage.
We recently compared the stability (by analytics) of Ronozyme HiPhos GT and two leading competitive phytase products over a 90-day storage period. This storage study was dovetailed with a feeding trial to evaluate the in vivo efficacy of the stored phytases. Our objective was to learn how pigs respond to phytases stored in summer conditions and extend this to include phytases stored in a vitamin-trace mineral premix (VTM). All trial work was completed by Vier, et al., (2018, unpublished) at Kansas State University who independently obtained the phytases.
What We Found
When stored in concentrate form –
● Ronozyme HiPhos experienced the least loss (-5%) in activity at day 30
● All phytase sources experienced considerable loss (40-47%) at day 90
When stored in a VTM –
● Loss in activity for all phytases was higher in VTM.
● On day 30 and 90, loss in activity was similar across phytases.
Although little difference in the retentions of phytase activity occurred across sources at day 90 of storage, two important features emerged:
● Retention of phytase was greatest during the first 30 days of storage, especially for the Ronozyme HiPhos GT and concentrated sources.
● According to pig performance, Ronozyme HiPhos GT in VTM and concentrate provided superior pig performance
These data demonstrate important differences exist in commercial phytases which are seldom exposed by simple analytics. Although the stability of phytases in pelleted diets is critical, other factors need to be considered. Even when mash feeds are utilized, processes and conditions affect the stability of phytase and final product quality. Ronozyme HiPhos GT from DSM consistently exhibits superior stability and efficacy for the best pig performance, whether added directly to feeds or through a VTM. And, it can save $3-7/ton on feed costs.