Abstract
Depending on the processing plant, gums and soapstocks may be added back to soybean meal. There is potential for these by-products to serve as an affordable energy source for swine due to their residual oil content. A total of 350 pigs (Line 241 × 600, DNA; initially 5.3 ± 0.02 kg) were weaned at approximately 19 d of age and used in a 42-d experiment. At weaning, pigs were randomly assigned to pens and allotted to 1 of the 5 treatments. There were 5 pigs per pen and 14 pens per treatment. Diets were fed in 3 phases: phase 1 from weaning to day 11, phase 2 from days 11 to 23, and phase 3 from days 23 to 42. Treatments included a control diet containing soybean meal with no added soybean by-products. Two additional diets contained gums or soapstocks at 4% of the soybean meal level in the diet. Another treatment diet contained soybean meal with 2% added soybean gums and 2% added soybean soapstocks. Finally, a negative control contained 4% less soybean meal with no added by-products to have equal protein from soybean meal to diets with added gums or soapstocks. Feces were collected on days 11 and 23 from 3 pigs per pen to determine fecal dry matter (DM). Fecal samples taken on day 23 were used to determine the apparent total tract digestibility (ATTD) of DM. From days 0 to 11 (phase 1) and days 11 to 23 (phase 2), there was no evidence of differences (P > 0.10) for any growth response criteria. From days 23 to 42 (phase 3), pigs fed soybean meal with added gums had increased (P = 0.05) average daily gain (ADG). However, there was no evidence for differences (P > 0.10) in average daily feed intake (ADFI) or gain-to-feed ratio (G:F). For the overall experimental period (days 0 to 42), there was no evidence of differences (P > 0.10) due to dietary treatment for ADG, ADFI, or G:F. Fecal DM was approximately 19% on both days 11 and 23 and was not affected (P > 0.10) by treatment. There was an interaction (P = 0.019) between soybean gum and soapstocks for the ATTD of DM. When adding 4% gums to the diet, there was an improvement in the ATTD of DM; however, there was no evidence of differences when adding 4% soapstocks or 2% gums and 2% soapstocks to soybean meal. These data suggest adding soybean processing by-products to soybean meal has minimal effects on nursery pig growth performance. However, there is a potential for improved ADG in the late nursery period when soybean meal containing added gums is included in the diet.