Effects of low acid-binding capacity specialty soy protein sources on nursery pig performance in a commercial environment

Two experiments were conducted to determine the effects of low acid-binding capacity (<b>ABC</b>) specialty soy protein sources on weanling pig performance. In experiment 1, 2,260 pigs, initially weighed 6.7 kg, were used to determine the effects of low ABC soy proteins as a replacement to poultry meal (<b>PM</b>) or spray-dried blood plasma (<b>SDBP</b>). Treatments were arranged in a 2 × 2 factorial plus a control diet fed in two phases. There were 20 or 21 pigs per pen with 22 replications (pens) per treatment. The control diet contained PM (AV-E Digest, XFE Products, Des Moines, IA) and SDBP (Appetein, APC Inc., Ankeny, IA). Specialty soy protein concentrate (<b>SSPC</b>; AX3 Digest, Protekta, Newport Beach, CA) and microbial-enhanced soybean meal (<b>MESBM</b>; MEPRO; Prairie Aquatech, Brookings, SD) were used to replace PM or PM and SDBP on a standardized ileal digestible Lys basis. From d 0 to 21 and d 0 to 42, pigs fed either soy protein source replacing PM had greater (<i>P </i>≤ 0.016) average daily gain (<b>ADG</b>) and average daily feed intake than pigs fed PM. From d 0 to 21, pigs fed SSPC had increased (<i>P </i>< 0.001) G:F compared with pigs fed MESBM and those fed either soy protein source replacing SDBP had increased (<i>P </i>= 0.044) G:F compared with pigs fed SDBP. In experiment 2, 1,057 pigs, initially weighed 6.2 kg, were used to determine the effects of diet ABC at a pH of 4 (<b>ABC-4</b>) with specialty soy proteins with or without pharmacological levels of Zn from ZnO. Experimental diets were fed in two phases with 22 pigs per pen and 12 replications per treatment. Dietary treatments were arranged in a 2 × 2 factorial with main effects of ABC-4 (low or high) and pharmacological levels of Zn from ZnO (105 or 2,000 mg/kg). The low ABC-4 diet without ZnO was formulated to 150 and 200 meq/kg using SSPC in phases 1 and 2, respectively. The high ABC-4 diet used enzymatically treated soybean meal (HP 300, Hamlet Protein, Findlay, OH) which increased the ABC-4 by 127 and 104 meq/kg in phases 1 and 2, respectively. From d 0 to 21 and d 0 to 42, there was an ABC-4 × ZnO interaction (<i>P </i>≤ 0.026) observed where pigs fed low ABC-4 diets had greater (<i>P </i>< 0.05) ADG and G:F than pigs fed high ABC-4 diets without ZnO, but when diets contained added ZnO, there were no differences based on ABC-4. In conclusion, low ABC specialty soy proteins can be used to achieve low dietary ABC-4 levels to improve the performance of weanling pigs and provide a similar response to those fed pharmacological levels of Zn.