266 Dietary strategies in diets without zinc oxide for nursery pigs

Abstract A total of 300 pigs (DNA 241 × 600; initially 4.2 kg) were used to evaluate the effects of different nutritional strategies to replace zinc oxide (ZnO) in nursery diets. Treatments consisted of A) Positive control (21% CP; ZnO providing 3,000 ppm Zn from d 0 to 7, and 2,000 ppm Zn from d 7 to 25); B) Negative control (NC; no ZnO); C) NC plus 1.2% Na diformate; D) NC with 4% coarse ground wheat bran; E) NC with low crude protein (18%) by adding high levels of feed grade amino acids; and F) the combination of NC with 18% crude protein (CP), 1.2% Na diformate, and 4% coarse ground wheat bran. There were 5 pigs per pen and 10 pens per treatment in a completely randomized design. Data were analyzed with the Proc Mixed procedure in SAS. For the overall period (d 0 to 46), pigs fed diets containing ZnO had greater (P < 0.001) ADG, ADFI, and final BW than other treatments, with pigs fed the NC with 18% CP having the lowest performance. Pigs fed the NC diet without any nutritional alternative had the lowest fecal dry matter (DM; P < 0.050) and highest fecal scores (P < 0.050). Pigs fed diets with ZnO had similar fecal DM and scores as pigs fed the diet containing the combination of 1.2% Na diformate, 4% coarse ground wheat bran, and low (18%) CP, but greater (P < 0.023) fecal DM than pigs fed the alternatives used individually. This study suggests none of the strategies used alone were effective at replacing ZnO while the use of low CP and amino acids reduced performance further. Combining the three alternatives tested as a replacement to ZnO improved fecal DM content and fecal score but did not result in improved growth performance.