The effects of enzymatically treated soybean meal on growth performance and intestinal structure, barrier integrity, inflammation, oxidative status, and volatile fatty acid production of nursery pigs

Authors: RUCKMAN, LEIGH - Iowa State University; PETRY, AMY - Iowa State University; GOULD, STACIE - Iowa State University; Kerr, Brian; PATIENCE, JOHN - Iowa State University

Submitted to: Translational Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/1/2020
Publication Date: 12/1/2020
Citation: Ruckman, L.A., Petry, A.L., Gould, S.A., Kerr, B.J., Patience, J.F. 2020. The effects of enzymatically treated soybean meal on growth performance and intestinal structure, barrier integrity, inflammation, oxidative status, and volatile fatty acid production of nursery pigs. Translational Animal Science. 4(3). Article etxaa170. https://doi.org/10.1093/tas/txaa170.
DOI: https://doi.org/10.1093/tas/txaa170

Interpretive Summary: The transition at weaning exposes pigs to multiple new stressors, leaving them susceptible to low feed intake and reduced growth, gastrointestinal tract disorders, and impaired intestinal function and integrity. Conventional soybean meal contains some anti-nutritional factors which if consumed in high enough concentrations, may negatively impact the growth and intestinal health of young pigs. Enzymatically-treated soybean meal, in contrast, has reduced levels of these anti-nutritional factors compared to conventional soybean meal, which may result in improved animal growth and decreased gastrointestinal tract disorders. The current study was conducted to determine the impact of diets in which enzymatically-treated soybean meal replaced increasing amounts of soybean meal on growth performance, intestinal structure and barrier integrity, inflammation, and oxidative status in newly weaned pigs. Data from this experiment indicated that feeding enzymatically-treated soybean meal, reduced pig performance when included above 7% of the diet, improved oxidative status and intestinal barrier integrity in nursery pigs, but had minimal effects on intestinal inflammation or morphology. This information is important for nutritionists at universities, feed companies, and pig production facilities for determining how enzymatically processing of soybean meal may affect animal growth and gastrointestinal tract function.

Technical Abstract: The objective of this experiment was to determine the impact of diets containing increasing amounts of enzymatically-treated soybean meal (ESBM) but decreasing amounts of soybean meal (SBM) on growth performance, intestinal structure and barrier integrity, inflammation, and oxidative status in weaned pigs. A total of 480 pigs [6.3 ± 1.2 kg body weight (BW)] were blocked by initial BW and pens (n = 12 per treatment) were randomly allotted to 1 of 4 dietary treatments. Diets were fed in 3 phases (d 0-14, 14-28, and 28-35) over a 35-d period. The 4 dietary treatments consisted of a negative control diet (NC), the NC with 7.0% ESBM (ESBM1), the NC with 14.0% ESBM (ESBM2), and the NC with 21.0% ESBM (ESBM3). Soybean meal was reduced proportionately in each treatment. In phase 2, ESBM inclusion was decreased by 50% (3.5%, 7.0%, and 10.5% ESBM, respectively); phase 3 was a common diet and contained no ESBM. Fecal score was visually ranked weekly using a 4-point scale. Intestinal tissue, digesta and blood samples were collected from 48 pigs (1 per pen) on d 10. Data were analyzed using PROC MIXED of SAS (9.4) with pen as the experimental unit; diet and block were considered fixed effects. Linear and quadratic contrasts were used to determine the effect of increasing ESBM. Overall, ESBM2 and ESBM3 decreased final BW, ADG, and ADFI compared to NC and ESBM1 (diet, P < 0.05; linear, P < 0.05). Overall fecal score (diet, P < 0.05) and fecal DM (P < 0.05) were improved by feeding ESBM diets compared to NC. Volatile fatty acid (VFA) concentration of acetate, propionate, butyrate, and total VFA in ileal contents increased as ESBM inclusion increased (P < 0.05). Colonic VFA concentration was not impacted (P > 0.10). Total antioxidant capacity was increased by ESBM (P < 0.05). The concentration of mucosal interleukin-4 increased as the inclusion of ESBM increased (linear, P < 0.05). Messenger ribonucleic acid abundance of occludin and zonula-occludens-1 in ileal tissue was increased by ESBM1 or ESBM2 (P < 0.05). In conclusion, increasing the dietary levels of ESBM over 7% had a negative impact on nursery pig performance, but ESBM positively impacted fecal score. Feeding ESBM improved oxidative status and intestinal barrier integrity while increasing ileal VFA production but had minimal impact on intestinal inflammation or morphology. Further research is needed to determine the optimal inclusion level of ESBM.