Abstract #M186

# M186
A comparison of total, apparent total-tract digestible, and standardized total-tract digestible phosphorus on excretion and digestibility of phosphorus in pigs.
W. B. Kwon*1, S. K. Park2, B. G. Kim1, 1Konkuk University, Seoul, Republic of Korea, 2Sejong University, Seoul, Republic of Korea.

An experiment was conducted to test a hypothesis that 3 diet formulation methods of using total, apparent total-tract digestible (ATTD), and standardized total-tract digestible (STTD) phosphorus (P) differ in excretion and digestibility of P in pigs. Twenty-four barrows with an initial BW of 18.1 ± 0.7 kg were randomly allotted to 3 dietary treatments with 8 replicate pigs per diet in a completely randomized design. Experimental diets were formulated to contain constant amounts of corn, soybean meal, whey powder, and dicalcium phosphate. The 3 diets were formulated based on a total, ATTD, or STTD basis to meet the dietary P requirement by changing the inclusion rate of rice bran at the expense of cornstarch and cellulose. Each experimental period consisted of a 4-d adaptation period and a 5-d fecal collection period. During the collection period, total feed intake did not differ among the treatments. The daily P intake and daily P output of pigs fed the diet based on ATTD P was greater (10.87 vs. 7.65 or 8.96 g/d and 4.27 vs. 2.60 or 3.30 g/d, respectively; P < 0.05) compared with the total P- or STTD P-based group. The ATTD of P was not different among the treatment groups. Taken together, formulating a diet based on total P or STTD P resulted in less P excretion mainly due to the less concentration of dietary P compared with a diet based on ATTD P. Further research is warranted to investigate performance and P retention in pigs fed diets formulated based on total P, ATTD P, and STTD P.

Key Words: diet formulation, phosphorus, swine