Nutritional And Environmental Benefits

Numerous studies have demonstrated the effectiveness of microbial or plant phytase added to plant-based diets for swine, poultry, and fish in improving utilization of phytate-phosphorus and reducing phosphorus excretion by these animals.[6] The efficacy of different phytases varies, but the average amount of phytase needed to replace 1 g of inorganic phosphorus per kg of swine or poultry diet ranges from 500 to 1000 units.[7] With this efficacy, phytase can obviate inorganic phosphorus supplementation at least by half, saving the nonrenew-able resource that may be exhausted in 80 years at the current extraction rate. More urgently, supplemental phytase reduces fecal phosphorus excretion by 30 50%, which can potentially eliminate 90,000 tons of phosphorus excreted to the environment by poultry and swine in the United States annually. In addition, phytase improves bioavailability of calcium, zinc, and iron, primarily by releasing these elements from binding to the phosphate groups of phytate. However, the effects of phytase on utilization of protein, amino acids, or energy are still controversial.

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