Effects of soybean gums and soybean soapstocks on weanling pig growth performance, fecal dry matter, and apparent total tract digestibility of dry matter

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.