Comparison of genetically engineered microbial and plant phytase for young broilers.

Researchers at Virginia Polytechnic Institute and State University have compared the efficacy of genetically engineered Aspergillus ficuum phytase, expressed in Aspergillus niger (Natuphos) or in canola seed (Phytaseed), for increasing the utilization of phytate phosphorus in corn-soybean meal diets for pigs and broilers.

In the poultry studies, three levels of each source of phytase (250, 500 and 2,500 U/kg of diet) was added to the corn-soybean meal base diet containing 0.46% total phosphorus, 0.21% nonphytate phosphorus and 0.92% calcium. Results indicated that both sources of phytase resulted in similar body weight gains; feed intake; feed efficiencies; apparent retention of dry matter; phosphorus and calcium; and toe ash measurements. Toxicity was not observed by feeding the 2,500 U/kg phytase level.

Zhang, Z.B. and co-workers. 2000. Comparison of genetically engineered microbial and plant phytase for young broilers. Poultry Sci. 78:709-717.