PSXVI-14 Hindgut Disappearance of Phosphorus in Corn-Soybean Meal-Based Diets with or without Inorganic Phosphorus Sources in Twenty-Four-kg Pigs

Abstract

The objective was to investigate the hindgut disappearance of phosphorus (P) in corn-soybean meal-based diets with or without inorganic P sources in pigs. Hindgut disappearance of P was hypothesized to be greater in a diet without inorganic P than in a diet with inorganic P. Barrows (n = 5; initial body weight = 23.5 ± 3.1 kg and final body weight = 33.7 ± 5.5 kg) fitted with a T-cannula in the distal ileum were individually housed in pens equipped with a feeder and a nipple drinker. Two corn-soybean meal-based diets were formulated with or without the inclusion of inorganic P. No phytase was supplemented to the diets. All diets contained 0.5% chromic oxide as an indigestible index. The pigs were allotted to a 2-period crossover design with 2 diets. A diet was fed to 2 pigs and the other diet was fed to 3 pigs in each period. An additional period was conducted after the 2 periods to obtain 2 additional replicates for each treatment. Each period consisted of a 7-d adaptation period, a 2-d fecal collection period, and a 2-d ileal collection period. Apparent ileal (54.7 vs. 35.0%) and total tract (53.7 vs. 34.3%) P digestibility values in the inorganic P-containing diet were greater (P < 0.01) than those in the diet without inorganic P. However, apparent ileal P digestibility values were comparable (P > 0.90) with apparent total tract P digestibility values irrespective of the inclusion of inorganic P in the diets, and thus, a significant amount of hindgut disappearance of P was not observed in both diets. In conclusion, hindgut disappearance of P in a corn-soybean meal-based diet was negligible in 23-kg growing pigs regardless of the inclusion of inorganic P sources.