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Effects of a xylanase and an emulsifier in diets with dried yeast on nursery pig performance
Two experiments evaluated the effect of using xylanase alone (XY) or with an emulsifier (XY+EM) in pigs fed increasing levels of dried yeast (DY). Both experiments were a RCBD; blocks were 3 BW categories × 2 nursery rooms. Each experiment had 8 dietary treatments in a 4 (DY at 0, 2.5, 5, or 10%) × 2 (None vs. XY+EM in Exp. 1, or None vs. XY in Exp. 2) factorial arrangement. Each treatment had 6 block-replicates; experimental units were pens with 4 pigs (~21-day old; 5.8±0.2 kg BW in Exp. 1, and 6.7±0.4 kg BW in Exp. 2). Sexes were kept balanced among treatments, within block. Performance was measured and feed was changed at the end of each feeding phase (n=4): days 7, 14, 28, and 42. Dietary treatments were fed for the full 42 days of the trial. Inclusion of DY (48% CP; 3,699 kcal ME/kg) replaced fish meal and soy protein concentrate from days 0-14, and then soybean meal from days 14-42. Xylanase (25 g enzyme/t) was added without consideration of energy or nutritional value. The emulsifier (8,527 kcal ME/kg) was added at 1% of diet replacing fat. Data were analyzed using the MIXED procedure of SAS; block was a random variable. Linear and quadratic polynomials were used to assess DY level. Dietary DY did not interact with XY+EM (Exp. 1) or XY (Exp. 2). In Exp. 1, inclusion of XY+EM improved (P<0.05) G:F (802 vs. 856 g/kg; SEM=17) on days 0-14, as well as the overall (d 0-42) ADG (411 vs. 432 g/d; SEM=17) and ADFI (608 vs. 636 g/d; SEM=29). In Exp. 2, no main effect of XY was detected. The inclusion of DY up to 10% of diet did not affect pig performance from days 0-14. In both experiments, increasing levels of DY reduced (linear, P<0.05) the overall (d 0-42) ADG (Exp. 1: 441, 424, 409, 411 g/d; SEM=18; and Exp. 2: 502, 491, 478, 464 g/d; SEM 13, for 0, 2.5, 5, and 10% DY, respectively). In conclusion, DY may be used up to 10% of the diet to replace fish meal and soy protein concentrate without affecting pig performance during the first 14 days post-weaning. Inclusion of XY+EM improves nursery pig performance, whereas XY alone did not.
Keywords: Xylanase, Emulsifier, Grain Distillers Dried Yeast