Evaluation of NutriDense low-phytate corn and added fat in growing and finishing swine diets.

Two experiments were conducted to evaluate the effects of NutriDense low-phytate corn in conjunction with increasing added dietary fat on growing and finishing pig performance. Diets in both experiments were corn-soybean meal-based, with yellow dent or NutriDense low-phytate corn and 0, 3, or 6% added choice white grease arranged in a 2 x 3 factorial design. There were 25 to 28 pigs per pen and 7 pens (replications) per treatment in both experiments. In Exp. 1, a total of 1,162 gilts with an initial BW of 44.6 kg were used in a 28-d growth study. A constant true ileal digestible (TID) Lys:ME ratio of 2.80 g/Mcal and available P:ME ratio of 0.90 g/Mcal were maintained in all treatment diets. Overall (d 0 to 28), there were no corn source x added fat interactions (P >/= 0.79). Regardless of corn source, ADG and G:F increased (linear, P = 0.03) with increasing added fat. There were no differences (P >/= 0.34) in pig growth performance between those fed NutriDense low-phytate or yellow dent corn. In Exp. 2, a total of 1,128 gilts with an initial BW of 81.6 kg were used in a 28-d growth study. A constant TID Lys:ME ratio of 2.15 g/Mcal of ME and available P:ME ratio of 0.75 g/Mcal were maintained in all treatment diets. Overall (d 0 to 28), there was a tendency (P = 0.07) for a corn source x added fat interaction for G:F, which can be explained by the improved G:F in pigs fed yellow dent corn only when 6% fat was added to the diet, whereas G:F was improved at both 3 and 6% added fat in pigs fed NutriDense low-phytate corn. There were no differences (P >/= 0.18) in growth performance between pigs fed NutriDense low-phytate or yellow dent corn. These results indicate that increasing added fat improved growth performance regardless of the corn source. In addition, growth performance was similar for pigs fed NutriDense low-phytate or yellow dent corn.