Phosphorous Digestibility and Activity of Intestinal Phytase in Hybrid Tilapia, Oreochromis niloticus x O. aureus

摘要

Experiments were concluded to determine the degree to whieh phytate-hound phosphorus from plant protein sources could be used by hybrid tilapia (Oreochromis niloticus x O. aureus). Utilizing an inert marker technique with chromic oxide, hybrid tilapiain our study were effective at utilizing both inorganic and phytate phosphorus as evidenced by average apparent digestibility values of 93.2% and 90.0% for total and phytate phosphorus, respectively. Analysis of the intestinal brush border membrane of the tilapia revealed enzyme activity that was capable of hydrolyzing phytic acid. The presence of phytic acid hydro-lyzing enz.yme activity in the intestinal brush border provides a probable mechanism by which these hybrid tilapia are able to utilize phytale phosphorus effectively.