Nonphytate phosphorus requirement and phosphorus excretion of broiler chicks fed diets composed of normal or high available phosphate corn with and without microbial phytase

Abstract

A study was conducted to evaluate the ability of the young (0 to 3 wk) broiler chicken to utilize the P provided by a high available P corn [HAPC; 0.27% total P and 0.17% nonphytate P] in comparison with yellow dent corn (YDC; 0.23% total P and 0.03% nonphytate P), and to determine the extent to which supplementation with exogenous phytase enzyme could reduce the demands for dietary P and subsequently reduce P excretion. Diets prepared using the two types of corn differed in the amount of phytate-bound P, with the HAPC diets containing approximately 50% less phytate-bound P. Treatment diets were prepared by varying the amount of dicalcium phosphate, and ranged from 0.10 to 0.50% nonphytate P for YDC diets, and from 0.18 to 0.50% nonphytate P for HAPC diets. Sublots of each diet were supplemented with 800 units/kg phytase. Each diet was fed to six pens of five male chicks of a commercial broiler strain from 1 to 21 d of age. Regression analysis was used to estimate nonphytate P requirements for each corn type with and without phytase supplementation. The greatest need for nonphytate P was for maximum tibia ash, with requirements of 0.39, 0.29, 0.37, and 0.32% in diets with YDC, YDC plus phytase, HAPC, and HAPC plus phytase, respectively. Addition of phytase liberated approximately 50% of the phytate-bound P from each diet. These levels were sufficient to support body weight, feed conversion, and livability. Fecal P content of broilers fed diets with YDC at the NRC (1994) recommended level of 0.45% nonphytate P was 1.21%, whereas at the respective requirement points indicated above, the P content was 1.09, 0.87, 0.78, and 0.64% in feces from broilers fed diets with YDC, YDC plus phytase, HAPC, and HAPC plus phytase, respectively. Thus, fecal P output could be reduced while maintaining optimum performance by the use of reduced dietary nonphytate P, introduction of HAPC, and phytase supplementation. One of the greatest benefits of phytase supplementation appeared to be maintaining livability at lower dietary levels of nonphytate P.

Reduction of the nutritional values of diets for hens through supplementation with phytase

“…A similar result was reported by Waldroup et al (2000) with the addition of 800 FTU in rations of hens from 1 to 21 days of age. Onyango et al (2003) also found a high correlation between the level of available P in the feed and the ash content in the shank of broiler chicks from 1 to 21 days of age.…”

Phosphorus digestibility in low-phytate barley fed to finishing pigs

“…Earlier work with low-phytate corn was also successful in improving phosphorus utilization for pigs (Veum et al 2001) and broilers (Li et al 2000;Yan et al 2000;Waldroup et al 2000).…”

An optimal dietary non-phytate phosphorus level of broilers fed a conventional corn–soybean meal diet from 4 to 6 weeks of age

“…In recent years, broken-line models have been often used for estimating dietary NPP requirements of broilers (Waldroup et al, 2000;Yan et al, 2001;Karimi et al, 2011). Therefore, in the present study, dietary NPP requirements of broilers have been evaluated by broken-line models.…”

“…A single large batch of the mash basal diet, void of CaHPO 4 ·H 2 O and CaCO 3 , was mixed at first, and then Table 1 The composition and nutrient levels of the complete diet for broilers at 1 to 3 weeks of age and the basal diet for broilers at 4 to 6 weeks of age (as-fed basis) (Waldroup et al, 2000;Yan et al, 2001;Liu, 2012). Fine sand was washed several times before use, and contained no detectable P and Ca.…”

“…Orthogonal comparisons were applied for linear or quadratic responses of dependent variables to independent variables. And then, broken-line models were set up by conducting non-linear regression analyses using the PROC NLIN procedure of SAS (Statistical Analysis Systems Institute Inc., 2003), and the breaking points of these broken-line models were estimated and defined as dietary NPP requirements of broilers (Yu and Morris, 1999;Waldroup et al, 2000). P-value was considered at P < 0.05.…”