Effect of high concentration of phytase supplementation on energy and nutrient digestibility of growing pigs fed with reduced dietary crude protein balanced with limiting amino acids

Abstract There is a need to improve pig production at least cost through various dietary manipulations and nutrient management strategies that will foster reduced environmental wastes of N, amino acids (AA), P, and Ca. This experiment was designed to estimate the effect of phytase supplementation on energy and nutrient digestibility of growing pigs fed with reduced dietary crude protein (CP) balanced with limiting AA. Experimental diets were formulated in a 3 × 2 factorial arrangement of 6 dietary treatments containing 3 CP concentrations (14, 16, and 18%) supplemented with or without 5,000 units phytase/g. Limiting AA of the diets were balanced using crystalline Lys, Met, Thr, and Trp. The 6 experimental diets were fed to 6 cannulated growing pigs (30.00 ± 2.10 kg) in a 6 × 6 Latin square arrangement of 6 diets and 6 periods. Fecal and ileal samples were collected to estimate the apparent and ileal digestibility of nutrients and energy. Apparent total tract digestibility (ATTD) of dry matter (DM), N, crude fibre, ether extract, and energy decreased (P