The effect of phytase source, wheat middlings, and citric acid on phosphorus utilization, growth performance, and carcass yield in broilers. (240)
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Keywords

Phytase
wheat middlings
broilers
citric acid

How to Cite

The effect of phytase source, wheat middlings, and citric acid on phosphorus utilization, growth performance, and carcass yield in broilers. (240). (2012). Tropical Agriculture, 89(4). https://journals.sta.uwi.edu/ojs/index.php/ta/article/view/997

Abstract

A study was conducted to investigate the impact of phytase source, citric acid, and wheat middlings (WM) on growth performance, bone strength, carcass yield, and P release in broilers fed marginally-deficient P diets from d 21 to 55. The experiment consisted of 13 dietary treatments, which were replicated five times, where each replicate consisted of 20 birds and utilized the standard-curve methodology using monobasic potassium phosphate (KH2PO4) as the standard. Treatments were as follows: diets 1 to 4) corn –soybean meal (C-SBM) basal (0.13% iP) supplemented with graded levels (0, 0.04, 0.08, 0.12%) of KH2PO4; diets 5 to 8) as in diet 1 with 500 FTU/kg of phytase (E. coli (EP) or fungal (FP)) and two levels of citric acid (0 or 3 %); diet 9) as in diet 1 with 10% corn replaced by WM; and diets 10 to 13) as in diet 9 supplemented with 500 FTU/kg of phytase (EP or FP) and two levels of citric acid (0 or 3 %). Reducing dietary IP had no impact on growth performance. Phytase had the main effect of increasing weight gain in the grower and withdrawal phases (P < 0.05); weight gain was greater in broilers fed the EP diets compared to those fed the FP diets during the grower phase (P < 0.05). When all the periods were combined only broilers fed the EP diets had weight gains and feed efficiencies that were greater than broilers fed no supplemental phytase (P < 0.05). The inclusion of phytase had the main effect of increasing adjusted bone breaking strength (ABBS) and tibia ash (P < 0.05) and released at least 0.083% P. Broilers fed the FP diets had lower carcass yield, whereas broilers fed the EP diets had lower wing yield (P < 0.05). Citric acid had the main effect of increasing feed efficiency, ABBS, and tibia ash (P <0.05) when all the periods were combined. Phytase and citric acid released at least 0.100% P, whereas the inclusion of WM alone released 0.051% P using ABBS data. The combination of phytase and WM increased P release by 67% (P <0.05), whereas phytase, citric acid, and WM released at least 0.148% P.
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