The effects of phytase supplementation on performance and phosphorus excretion from broiler chickens fed low phosphorus-containing diets based on normal or low-phytic acid barley

Authors: THACKER, PHILIP - UNIV. OF SASKATCHEWAN; HAQ, INAM - UNIV. OF SASKATCHEWAN; WILLING, BENJAMIN - UNIV. OF SASKATCHEWAN; Leytem, April

Submitted to: Asian-Australasian Journal of Animal Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/1/2009
Publication Date: 3/1/2009
Citation: Thacker, P.A., Haq, I., Willing, B.P., Leytem, A.B. 2009. The effects of phytase supplementation on performance and phosphorus excretion from broiler chickens fed low phosphorus-containing diets based on normal or low-phytic acid barley. Asian-Australasian Journal of Animal Sciences. 22(3):404-409.

Interpretive Summary: : Long term application of poultry manure can lead to soil phosphorus (P) accumulation and the potential P transport into waterbodies which can contribute to eutrophication of freshwater systems. One reason for this accumulation of soil P is due to the inefficiency of poultry to utilize the P in feed ingredient, such as phytate, and therefore much of the P is excreted in the manure. The development of low phytate grains and the addition of phytase to feed has improved the P utilization by poultry, therefore decreasing the amount of P excreted into the environment. At present, the combined effect of utilizing low phytate grains with phytase addition has not been tested. Therefore, the objective of this experiment was to determine the effects of phytase supplementation on performance and P excretion from young broilers fed diets containing low-phytate barleys formulated without a source of inorganic P. The overall results of this study indicate that as a consequence of the increased availability of P in low-phytate barley, it may be possible to reduce the amount of inorganic P used when formulating diets with low phytate barley compared with the levels needed when formulating diets with normal phytate barley. However, it is not possible to completely replace the inorganic P in diets containing low phytate barley without impairing poultry performance. The addition of phytase to low P containing diets formulated with low-phytate barley modestly improved body weight gain and feed intake while reducing broiler mortality. Feeding lower levels of supplementary inorganic P in combination with low phytate barley resulted in a significant reduction in P excretion by poultry. This will allow poultry producers who feed low phytate barley to produce poultry meat in a more environmentally friendly manner than occurs with normal barley thereby helping to minimize the environmental impact of intensive poultry operations. Feeding low-phytate barley would appear to offer poultry producers both economic and environmental benefits in the same package.

Technical Abstract: : Long term application of poultry manure can lead to soil phosphorus (P) accumulation and the potential P transport into waterbodies which can contribute to eutrophication of freshwater systems. One reason for this accumulation of soil P is due to the inefficiency of poultry to utilize the P in feed ingredient, such as phytate, and therefore much of the P is excreted in the manure. The development of low phytate grains and the addition of phytase to feed has improved the P utilization by poultry, therefore decreasing the amount of P excreted into the environment. At present, the combined effect of utilizing low phytate grains with phytase addition has not been tested. Therefore, the objective of this experiment was to determine the effects of phytase supplementation on performance and P excretion from young broilers fed diets containing low-phytate barleys formulated without a source of inorganic P. The overall results of this study indicate that as a consequence of the increased availability of P in low-phytate barley, it may be possible to reduce the amount of inorganic P used when formulating diets with low phytate barley compared with the levels needed when formulating diets with normal phytate barley. However, it is not possible to completely replace the inorganic P in diets containing low phytate barley without impairing poultry performance. The addition of phytase to low P containing diets formulated with low-phytate barley modestly improved body weight gain and feed intake while reducing broiler mortality. Feeding lower levels of supplementary inorganic P in combination with low phytate barley resulted in a significant reduction in P excretion by poultry. This will allow poultry producers who feed low phytate barley to produce poultry meat in a more environmentally friendly manner than occurs with normal barley thereby helping to minimize the environmental impact of intensive poultry operations. Feeding low-phytate barley would appear to offer poultry producers both economic and environmental benefits in the same package.