Estimation of apparent and true total tract digestibility of phosphorus from monocalcium phosphate in broiler diets

The aim of this trial was to determine the apparent and true total tract digestibility of phosphorus from monocalcium phosphate, as an inorganic P source in a broiler diet. The trial included 300 one-day-old broiler chickens (Cobb 500), which were randomly divided into three groups - by one hundred birds each. The experiment lasted 42 days, and was divided into three periods (days 1-21 for starter, days 21-35 for grower, and days 35-42 for finisher). One group of broilers was fed a diet without the addition of MCP (basal diet), and the other two experimental groups received different monocalcium phosphates. Cr2O3 was added to the diets at a 0.5% level as an indigestible marker. The production results (average body weight, average daily gain, feed intake and feed to gain ratio) were monitored during the trial. At day 11 and day 25, 10 birds from each group were placed into individual balance cages, in order to provide the collection of faeces during 5 consecutive days. The apparent and true total tract digestibility of P, as well as the apparent total tract digestibility of Ca were determined. Results showed that apparent total tract digestibility of P was influenced by the source of inorganic P (P<0.001). It was concluded that the utilisation of P was not significantly affected by the age of broilers, and the level of digested Ca did not represent the limiting factor for P digestibility in this experiment.