Investigation on bioavailability of rumen bacterial and protozoal phosphorus using a chick-model

Ruminal bacteria and protozoa provide excellent organic phosphorus (P) sources for the host animal. This experiment was conducted to compare the bioavailability of bacterial and protozoal P in comparison with that of dicalcium phosphate (DCP) as a reference phosphorus source. Bacteria and protozoa were isolated from the rumen contents of dairy cows and the chick-model was used to determine the phosphorus bioavailability. Fifteen day-old chicks were used in a completely randomized design with 4 treatments consisting of a control diet (without P, as a basal diet), bacterial P涫 diet, protozoalP涫 diet, and DCP涫 diet. Phosphorus balance was selected as the response criterion for phosphorus bioavailability assessment, using multiple linear regressions. The results showed a higher phosphorus bioavailability of protozoal P and DCP compared with bacterial P (P