The effect of dietary microbial phytase on mineral digestibility determined throughout the gastrointestinal tract of the growing pig fed a low-P, low-Ca corn-soybean meal diet

The study aimed to determine the impact of dietary microbial phytase supplementation on the apparent digestibility of minerals, other than P and Ca, throughout the gastrointestinal tract of the growing pig. Thirty-two entire male pigs (approximately 22 kg bodyweight) were allocated equally to three dietary treatments. All diets were corn-soybean meal diets deficient in P and Ca and were either not supplemented with microbial phytase or supplemented with microbial phytase at 1107 and 2215 U/kg respectively. Titanium dioxide was included in the diets as an indigestible marker. The pigs received their respective diets for 42 days and faecal samples were collected over days 40–42. On day 43, stomach chyme, terminal jejunal and terminal ileal digesta were collected post-euthanasia. Na, K, Mg, Fe, S, Cu, Mn and Zn were determined in the diets, chyme, digesta and faecal samples and apparent mineral digestibility was determined at the gastric, jejunal, ileal and total tract levels. Apparent mineral digestibility was different (P<0.01) across gastrointestinal tract locations. However, dietary microbial phytase supplementation had no effect (P>0.05) on the apparent digestibility of any of the minerals examined at any of the gastrointestinal tract locations.