Effect of calcium level and phytase addition on ileal phytate degradation and amino acid digestibility of broilers fed corn-based diets

Amerah, A. M., Plumstead, P. W., Barnard, L. P. and Kumar, A. (2014) Effect of calcium level and phytase addition on ileal phytate degradation and amino acid digestibility of broilers fed corn-based diets. Poultry Science, 93 4: 906-915. doi:10.3382/ps.2013-03465


Author Amerah, A. M.
Plumstead, P. W.
Barnard, L. P.
Kumar, A.
Title Effect of calcium level and phytase addition on ileal phytate degradation and amino acid digestibility of broilers fed corn-based diets
Journal name Poultry Science   Check publisher's open access policy
ISSN 1525-3171
0032-5791
Publication date 2014-04-01
Year available 2014
Sub-type Article (original research)
DOI 10.3382/ps.2013-03465
Open Access Status DOI
Volume 93
Issue 4
Start page 906
End page 915
Total pages 10
Place of publication Cary, NC, United States
Publisher Oxford University Press
Language eng
Formatted abstract
This study investigated the effect of dietary Ca to available P (AvP) ratio and phytase supplementation on bone ash, ileal phytate degradation, and nutrient digestibility in broilers fed corn-based diets. The experimental design was a 4 × 2 factorial arrangement of treatments evaluating 4 Ca:AvP ratios (1.43, 2.14, 2.86, and 3.57) and 2 levels of phytase (0 and 1,000 phytase units/kg of feed). The 4 Ca:AvP ratios were achieved by formulating all diets to a constant AvP level of 0.28% and varying Ca levels (0.4, 0.6, 0.8, and 1.0%). Each treatment was fed to 6 cages of 8 male Ross 308 broilers from 5 to 21 d. At 21 d, digesta from the terminal ileum was collected and analyzed for energy, phytate, P, Ca, and amino acids (AA) to determine digestibility. Digesta pH was measured in each segment (crop, gizzard, duodenum, and ileum) of the digestive tract. Data were analyzed by 2-way analysis of covariance. There was a significant interaction between dietary Ca:AvP ratio and phytase supplementation for weight gain (WG), feed intake (FI), and feed conversion ratio (FCR). In diets with no phytase, Ca:AvP ratio had a greater effect on WG, FI, and FCR compared with those fed diets without phytase. The orthogonal polynomial contrasts showed that the increase in dietary Ca:AvP ratio significantly decreased WG and FI in a quadratic manner, whereas FCR increased (P < 0.05) linearly with higher dietary Ca:AvP ratio. Increasing dietary Ca:AvP ratio led to a significant quadratic decrease in phytate degradation and significant linear decreases in P digestibility and bone ash. Phytase addition increased (P < 0.05) phytate degradation and improved (P < 0.05) energy, AA, and P digestibility at all levels of Ca:AvP with no interaction (P > 0.05) between the main factors. Digestibility of AA was positively correlated (P < 0.05) with the degree of phytate degradation. Increasing dietary Ca:AvP ratio significantly increased gizzard pH in a linear manner. In conclusion, phytase (1,000 phytase units/kg of feed) improved phytate, and P and AA digestibility at all Ca:AvP ratios evaluated in this study.
Keyword Broiler
Available phosphorus
Calcium
Amino acid
Phytate degradation
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Agriculture and Food Sciences
Official 2015 Collection
 
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