Challenges for efficient use of phytase in fish nutrition

Abstract

Phosphorus is stored in plants majorly in the form of phytic acid (IP6), which represents 50–80% of the total phosphorus present in the vegetable ingredients. As it is indigestible by nonruminant animals and remains negatively charged in the physiologic pH, it binds to a large variety of nutrients, mainly cations, which are discarded via feces. This leads to the addition of available phosphorus, which increases the cost and environmental problems. Therefore, the utilization of phytase helps to break IP6 and increases the use of the unavailable phosphorus. Phytase is successfully used in poultry and pigs feeding, whereas for fish, the results are ambiguous. Phytase acts in an optimum range of temperature and pH and denatures when subjected to extremes conditions. Thus, feed processing (extrusion) and the anatomical and physiological conditions of the fish species challenge its molecular integrity and activity. Hence, understanding the main aspects based on the results obtained by the use of phytase in fish feeding leads to optimal utilization of this enzyme due to its ideal activity and the challenges induced by processing and the fish species.

Keywords

• Eutrofização, Fitato, fósforo, pH, temperatura