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Encapsulation of microbial phytase to improve phosphorus digestibility from salmonids diet



Phytase is an enzyme that increases the availability of phosphorus in plant food proteins. It makes phytic acid phosphorus available (composed of plant proteins not readily available to salmonids), which results in a reduction in the excretion of phosphorus. Because phytase is heat sensitive, it must be protected by means of encapsulation during the feed manufacturing process or sprayed on pelleted feed. The purpose of this project is to develop an innovative strategy for encapsulation of phytase to protect its activity. Its specific objectives are to: characterize and optimize in vitro the model of liberation of bovine albumin in bovine serum through an alginate-chitosan-based hydrogel; to measure in vitro the activity of encapsulated and non-encapsulated phytase under conditions that stimulate gastric digestion, then determine the impact of the manufacture and storage of feed on phytase activity. It will also study the effects of the encapsulation of phytase on nutrient digestibility in rainbow trout and assess the extent to which this technique reduces nutrient concentrations in fish wastes. This project should ultimately lead to the development of innovative chemical polymer technology to direct the delivery of dietary enzymes in rainbow trout, thereby reducing phosphorus excretion.

Program Name

Aquaculture Collaborative Research and Development Program (ACRDP)


2002 - 2005



Principal Investigator(s)

Grant Vandenberg
Email: grand.vandenberg@fsaa.ulaval

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