ABSTRACT:
The aim of this study was to determine endogenous losses and true total digestibility of phosphorus (P) in piglets fed with diets containing rice bran (RB), and supplemented or not with phytase. The experiment was divided into three periods of 12 days each, seven for adaptation and five for total feces collection, with an interval of three days between periods. Twelve barrows with average body weights of 13.40±1.00kg at 46 days of age were distributed among six treatments consisting of diets formulated with three levels of RB (5%, 10%, and 20%) with or without the addition of 750FTUkg-1 of phytase. The amount of total daily feed was divided into four daily meals and water was available ad libitum. The method of total feces collection was used with ferric oxide as the fecal marker. The total consumption of P of RB origin was 0.37, 0.85 and 1.73gd-1 for concentrations of 5%, 10% and 20% of RB, respectively. Both RB and phytase levels had an effect on the apparent digestibility of P in RB. Results of the regression analysis of ingested P originating from the RB and absorbed P indicated endogenous losses of 527mg of Pkg-1 of dry matter intake, independent of phytase. Additionally, the true digestibility of P in RB was 47%, and it was not influenced by the inclusion of phytase. We concluded that the addition of 750FTU of phytase does not affect endogenous losses or the true digestibility of P in RB.
Key words:
endogenous losses; phytase; regression; total collection
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