Strategies to determine the efficacy of multiple phytase use at low activities using Ross x Ross 708 male broilers from 0 to 14

Authors: ENNIS, COURTNEY - Mississippi State University; GEHRING, CURRAN - Ab Vista; BEDFORD, MIKE - Ab Vista; WYATT, CRAIG - Ab Vista; WAMSLEY, KELLEY - Mississippi State University

Submitted to: Journal of Applied Poultry Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/18/2020
Publication Date: 12/12/2020
Citation: Ennis, C.E., Gehring, C.E., Bedford, M.R., Wyatt, C.L., Wamsley, K.G. 2020. Strategies to determine the efficacy of multiple phytase use at low activities using Ross x Ross 708 male broilers from 0 to 14. Journal of Applied Poultry Research. 29(4):977-994. https://doi.org/10.1016/j.japr.2020.09.006.
DOI: https://doi.org/10.1016/j.japr.2020.09.006

Interpretive Summary: Not all ingredients contain nutrients that are 100% available; therefore, enzymes are commonly added in commercial broiler diets to help birds utilize more nutrients out of the feed. The most common enzyme used is a phytase, which predominately helps birds digest more calcium and phosphorus from the feed. There are a multitude of commercially available phytases and not all phytases work the same way. Additionally, even the best phytases have not been shown to make all of the indigestible calcium and phosphorus available to the bird and thus, other ingredients need to be added into the feed and nutrients that are not utilized by the bird may cause concern for the environment. This research tested low inclusions of multiple phytases with varying modes of action (alone and in combination) to see if they can work together to make the indigestible calcium and phosphorus already in the diet, to be as close to 100% digestible as possible. This study focused on the starter phase (up to 14 days) because this phase is most sensitive for bird bone development. Bone and digesta samples, along with bird feed intake and weight were obtained to determine the best phytase application strategy. The best combination was determined to be all three of the phytases tested (combined into one diet), at the highest inclusions. More research using different diets and inclusion levels of the tested phytases is needed to verify the potential to enhance the entire grow-out cycle of the bird.

Technical Abstract: Phytase inclusion provides broiler production advantages such as improved growth performance and better nutrient digestibility. These effects become heightened in response to more complete degradation of IP6 and its lower esters to prevent chelation of nutrients. Therefore, strategies for the complete removal of the total phytate pool are being investigated to maximize the benefits previously mentioned. The unique biochemical properties amongst commercial phytases may provide an opportunity for a more coordinated and efficacious approach to dephosphorylation if fed together. Therefore, 3 phytases (A, B, and C) were evaluated for potential synergistic action in breaking down on phytate using phytase inclusion strategies (PIS; A, B, C, AB, AC, BC, or ABC) at either 120 or 240 FTU/kg using 0–14 d chick performance, as well as tibia ash and ileal measurements (digestibility and IP esters). Positive and negative control (PC; NC) diets were formulated to contain 0.8% Ca and 0.4% nonphytate P (nPP) and 0.4% Ca and 0.20% nPP, respectively. Feeding NC + ABC at 240 FTU/kg led to improved BW gain and tibia ash percentage. Reduction of IP6/IP5 and increased IP isomers were found with NC + PIS treatments vs. PC, with benefits for PIS treatments at 240 FTU/kg. Supplementation of NC + B, C, and BC at 240 FTU/kg increased IP4 compared with PC. Digestibility data were inconsistent; however, improvements were demonstrated with feeding NC + B and BC at 240 FTU/kg. These data demonstrate a potential synergy with NC + ABC at 240 FTU/kg. Further research should investigate the effects of PIS with various diet specifications and at higher phytase activity levels.