PSVII-2 Influence of source and concentration of phosphorus on apparent ileal digestibility and apparent total tract digestibility of phosphorus in growing pigs

Abstract

Abstract A study was conducted to examine the influence of source and concentration of phosphorus (P) on the apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of P in growing pigs. Six diets were formulated in a 2 × 3 factorial arrangement with soybean meal (SBM) or corn distillers’ dried grain with solubles (DDGS) as sole sources of dietary P, and concentration of P at 2.0, 2.5 or 3.0 g/kg. Eighteen cannulated pigs (initial BW = 40 ± 5 kg) were allotted to triplicate 6 × 3 incomplete Latin square design with 6 diets and 3 periods, which consisted of 5 d adaption, 2 d fecal collection, and 2 d ileal digesta collection. The results indicated that AID of P was not different from ATTD of P in all diets (P = 0.45). The digestibility of P was affected by source of P (P < 0.01), with mean of 33.7% in SBM and 50.3% in DDGS. The AID of P in SBM increased linearly (P < 0.05) with increasing P concentrations; however, there was no effect of increasing P concentrations on AID and ATTD of P in DDGS. Determined by regression analysis, true ileal digestibility of P was 58.3% or 57.6%, and true total tract digestibility of P was 56.0% or 62.6%, for SBM or DDGS respectively. The estimated ileal endogenous P loss was 0.61 or 0.13 g//kg DMI, and total tract endogenous P loss was 0.53 or 0.35 g/kg DMI, for SBM or DDGS respectively. In summary, source and concentration of dietary P affect the digestibility of P in growing pigs but there was no difference between AID and ATTD of P.