Phytase assay is not always a reliable indicator

摘要

The use of phytase in monogastric diets has increased dramatically in the past five years as a result of its capacity to improve metabolisability of several key, high value nutrients. Some of these nutrients, calcium and phosphorus in particular, playa critical role in bone development. As a result, whilst there is great interest in the use of phytase with regards to the potential formulation savings, there is also the concomitant concern of catastrophic losses in the event of failure to deliver thefunctioning enzyme to the bird. Such concerns are a consequence of the proteinaceous nature of phytases that renders them susceptible, to varying degrees, to thermal denaturation. Indeed, in vivo efficacy may be compromised or even fail if conditions of processing are too severe. As a result, feed manufacturers often rely on in-feed assays to provide assurance that the correct dose has been delivered to the animal. In some cases such reliance may be misplaced.