Improving phytate phosphorus utilization by adding phytase to low protein, phosphorus and calcium corn-soybean broiler diets [electronic resource].

Includes reference.

Two hundred and eighty eight one-day old unsexed Arbor Acres broiler chicks were used to evaluate the effect of microbial phytase enzyme supplementation to broiler corn-soybean meal diets low in crude protein (CP), inorganic P (IP) and Ca on the utilization of phytate P. Eight treatments with three replicates (12 birds/rep.) per treatment were used. Positive control and three basal diets were formulated. The positive control diet contained 22/20% CP, 0.45/0.39% IP and 1.00/0.90% Ca (starter/grower). Basal 1, 2 and 3, low IP, contained 0.30/0.25%; basal 3, low Ca, contained 0.67/0.60%; (starter/grower). Microbial phytase was supplemented with 0 and 1000 FTU/kg diet for the control and the three basal diets. Birds growth performance, bone mineralization, carcass characteristics, blood parameters and economical efficiency were evaluated. Results of the overall period (1-6 wks) showed that phytase supplementation to control diet improved growth performance. Reducing CP (20/18%) only or with low IP (0.30/0.25%) decreased body weight gain (BWG) and daily feed intake (DFI) and worsened (P≤ 0.05) feed conversion ratio (FCR). However, the addition of phytase (1000 FTU/kg) to low CP only or with low IP diets increased BWG and improved (P ≤ 0.05) FCR and values were comparable to those of the control. The reduction of Ca (0.67/0.60%) in bird low CP-IP diet decreased BWG and worsened (P≤ 0.05) FCR compared to that of the control. Supplementation of phytase to low CP-IP-Ca diet restored (P ≤ 0.05) BWG and FCR and values were even better than those of the control. Tibia ash increased (P ≤ 0.05) when phytase was added to all diets, with no significant differences between control and the three basal supplemented diets. Plasma Ca decreased (P ≤ 0.05) when phytase was added to low CP-IP-Ca diet in comparison with all treatments. Phytase numerically elevated plasma P with significant differences only when added to low CP-IP diet. Phytase increased (P ≤ 0.05) plasma protein when added to low CP diets. Except the abdominal fat, experimental treatments had no significant effect on carcass characteristics. While abdominal fat was increased (P≤ 0.05) with control + phytase diet, it was decreased (P≤ 0.05) with low CP-IP + Phytase diet. Supplementation of phytase to low CP, low CP-IP and Low CP-IP-Ca diets increased relative economical efficiency (REE) over those with no supplementation and over the control diet with phytase. In conclusion, phytase supplementation to low CP-IP-Ca broiler diet significantly improved BWG, FCR and tibia ash (%) and resulted in the highest REE.

Summary in Arabic.

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