COMMERCIAL PHYTASE USE IN PACU (Piaractus mesopotamicus)

Phosphorous is one of the most essential nutrients for fi sh. However, an excess of this mineral in fi sh diets in phytate form can lead to higher levels of excreted phosphorous. The phytase enzyme is responsible for the conversion of phytate into organic phosphorous, although it has been suggested that fi sh do not produce this compound, requiring the use ofa commercial enzyme . In this context, Natuphos® eff ects on pacu were evaluated through plasma osmolality and ionic level assessments to verify if commercial phytase is able to reduce phosphorous excretion by chelate cleavage, for example. Results: The best composition to be applied as fi sh feed additive for Pacu is a plant protein source containing 0.39% total phosphorus supplemented with 3000 phytase units/kg in liquid form. Conclusion: Phytase promotes increases in magnesium concentrations only, suggesting chelate cleavage improves phosphorus absorption. The application of phytase in other species should be considered.