A total of 2,260 pigs (initially 6.7 ± 0.3 kg) were used to evaluate specialty soy protein sources as alternatives to poultry meal and spray-dried blood plasma on nursery pig performance. At weaning, pigs were allotted to 1 of 5 dietary treatments based on initial weight in two research nurseries. In the first facility there were 20 pigs per pen and 10 pens per treatment. In the second facility, there were 21 pigs per pen and 12 replications per treatment for a total of 22 replications per treatment. Pigs were fed experimental diets during phase 1 (d 0 to 7) and phase 2 (d 7 to 21) followed by a common diet for an additional 21 d (d 21 to 42). Dietary treatments included a control diet containing 9.5% poultry meal (AV-E Digest, XFE Products, Des Moines, IA) and 4.13 (phase 1) or 2.75% (phase 2) spray-dried blood plasma (Appetein, APC Inc., Ankeny, IA) and a 2 × 2 factorial with a novel soy protein concentrate (AX3 Digest; Protekta; Plainfield, IN) or microbial enhanced soy protein (MEPro; Prairie Aquatech; Brookings, SD) replacing poultry meal or poultry meal and spray-dried blood plasma. Protein sources were added to the diet to maintain a similar level of soybean meal and balance for SID amino acids. Thus, soy protein sources were added to the diet at 6 and 13 (phase 1) or 10.75% (phase 2) to replace poultry meal or poultry meal and spray-dried blood plasma, respectively. Dietary treatment structure allowed the opportunity to compare each protein source to each other, soy protein sources as a replacement to poultry meal, and soy protein sources as a replacement to spray-dried blood plasma. During the experimental period (d 0 to 21), pigs fed novel soy protein concentrate had improved (P < 0.001) G:F with no differences (P > 0.10) in ADG or ADFI compared to pigs fed microbial enhanced soy protein. Pigs fed either soy protein as a replacement of poultry meal had increased (P < 0.001) ADG and ADFI compared to pigs fed the control diet. Additionally, pigs fed either soy protein source as a replacement of spray-dried blood plasma had improved (P = 0.044) G:F compared to pigs fed either soy protein without replacing spray-dried blood plasma, with no differences (P > 0.10) in ADG or ADFI.
In summary, utilizing a specialty soy protein source as a replacement for poultry meal improved growth performance. Further replacing poultry meal and spray-dried blood plasma with the specialty soy proteins improved feed efficiency during the experimental period. The novel soy protein concentrate improved feed efficiency compared to microbial enhanced soy protein during the experimental period with no effect on ADG or ADFI.