Evaluation of increasing levels of a microbial phytase in phosphorus deficient broiler diets via live broiler performance, tibia bone ash, apparent metabolizable energy, and amino acid digestibility

Abstract

The objective was to investigate increasing concentrations of an evolved microbial phytase on male broiler performance, tibia bone ash, AME, and amino acid digestibility when fed diets deficient in available phosphorus (aP). Experiment 1 evaluated the effects of phytase during a 21 d battery cage study and Experiment 2 was a 42 d grow-out. Experiment 1 included six treatments; negative control (NC) with an aP level of 0.23% (starter) and 0.19% (grower), two positive controls (PC) consisting of an additional 0.12% and 0.22% aP (PC 1 and PC 2), and the NC supplemented with three levels of phytase (250, 500, and 2,000 U/kg). The NC diet reduced (P < 0.05) FC, BW, and bone ash. Phytase increased (P < 0.05) BW with 2,000 U/kg phytase yielding similar results to the PC2, and improved FCR and increased bone ash was observed at all phytase levels. Amino acid digestibility coefficients were increased (P < 0.05) with phytase at 250 U/kg. Phytase at all rates increased (P < 0.05) AME to levels similar level as PC diets. Linear regression analysis indicated average P equivalency values for BW and bone ash of 0.137, 0.147, and 0.226 for phytase inclusion of 250, 500, and 2000 U/kg, respectively. Experiment 2 included a PC consisting of 0.45%, 0.41%, and 0.38% aP for the starter, grower, and finisher, respectively; NC with reduced aP of 0.17%; and phytase at 500 and 2,000 U/kg. Phytase increased BW (P < 0.05) compared to the NC as 2,000 U/kg phytase resulted in further BW increases compared to the PC (starter and grower). Phytase improved FCR to levels comparable to the PC, with supplementation at 2,000 U/kg resulting in improvements beyond the PC in the starter phase. Amino acid digestibility coefficients were increased with phytase at 2,000 U/kg to levels comparable to that of the PC. These data confirm that the inclusion of phytase improves broiler performance and bone mineralization in aP reduced diets and levels beyond the traditional 500 U/kg can result in further improvements.

Effects of Adding Phytase from <i>Aspergillus niger</i> to a Low Phosphorus Diet on Growth Performance, Tibia Characteristics, Phosphorus Excretion, and Meat Quality of Broilers 35 days after hatching

“…Previous studies have shown that broilers fed diets supplemented with phytase improved P retention by 50-60% (Simons et al, 1990;Kornegay et al, 1996). Pieniazek et al (2016) reported that super dosing of phytase beyond the industrial level not only increase the P availability, but also the availability of other nutrients such as proteins, lipids, carbohydrates, Ca 2+ , Cu 2+ , and Zn 2+ as a result of elevated hydrolysis by phytase. Phytase also lowering the global feed industry cost by reducing the cost of nutritional inputs, for example, by replacing inorganic P sources such as dicalcium phosphate (DCP) (Mrigen, 2009).…”

Effects of dietary 1 alpha-hydroxycholecalciferol in calcium and phosphorous-deficient diets on growth performance, tibia related indices and immune responses in broiler chickens

“…Several methods have been investigated to improve available PP utilization. Supplementations of low P diets with phytase have been shown to improve dietary P digestibility in sows ( Torrallardona et al., 2012 , Sands et al., 2001 ) and broilers ( Jiang et al., 2013 , Pieniazek et al., 2017 , Woyengo et al., 2010 , Ravindran et al., 2006 ). Consistently, Pillai et al.…”

Assessment of a Nutritional Rehabilitation Model in Two Modern Broilers and Their Jungle Fowl Ancestor: A Model for Better Understanding Childhood Undernutrition

“…However, 1995 broilers in the rye–corn group had stronger tibias than those birds fed rye in the second phase of the experiment indicating some recovery in bone strength has occurred. Tibia bone ash improved when a low phosphorus diets were supplemented with phytase, suggesting that the enzyme increased mineral availability ( 62 ). Therefore, it likely that switching from a rye to a corn-based diet increased mineral availability allowing for improved bone quality in modern and 1995 broilers.…”