EFFECT OF USING DIFFERENT LEVELS OF AVAILABLE PHOSPHORUS AND MICROBIAL PHYTASE ON THE PERFORMANCE OF BROILER CHICKS.

  

Abd El-Hakim, A. S.

Anim . Poultry Res. Inst ., Agric . Res . Cent . Dokki , Cairo, Egypt. [email protected]

Abstract:

 

The objective of this work was to evaluate the effect of low dietary phosphorus levels supplemented with different levels of microbial phytase on the growth performance, digestibility coefficients, carcass characteristics and content of calcium and phosphorus in tibia bone of broiler chicks. A total number of 240 one day unsexed Arbor Acres broiler chicks were used in this study. At the 7th day of age, birds were distributed into 8 experimental treatments. Two different levels of available phosphorus (PL1 and PL2) with three different levels of phytase supplementation (EZ1, EZ2 and EZ3) in (2x3) factorial design. In addition, two groups of chicks were fed on diets formulated without or with animal protein sources and used as control groups.

 

Results indicated that chicks fed on 0.40% phosphorus level (PL1) gained significantly better than those fed on 0.35% phosphorus level (PL2) during starting-growing period (2-3 weeks of age) while no significant effect was detected in body weight gain during finisher and overall period. The chicks fed on PL1 consumed significantly more feed during finisher and overall period than those fed on PL2. The best feed conversion value was recorded for chicks fed on PL2 during finisher and overall period. No significant effects were detected related to either phosphorus levels or phytase supplementation levels on the carcass characteristics or the content of calcium and phosphorus in tibia bone. Chicks fed on EZ3 recorded significantly improvement in protein digestion coefficient. The best values of the relative economic efficiency were recorded for chicks fed on PL2 with all levels of phytase supplementation. The overall results showed that the chicks could be fed on 0.40% phosphorus level with any level of phytase during starter-grower period and then switched to 0.35% phosphorus level with high level of phytase supplementation (1000 FTU) during the finisher period without any adverse effect on growth performance.