Fiber deprivation and insoluble corn-based fibrous co-products modulate gastrointestinal mucosa-associated microbiota, extracellular matrix remodeling, and intestinal morphology in growing pigs

Authors: MILLER, HANNAH - University Of Missouri; SASSER, CASSIDY - Texas Tech University; HERNANDEZ, SEBASTIAN - Texas Tech University; LEGAKO, JERRAD - Texas Tech University; ANDERSON, CHIRON - Iowa State University; SCHMITZ-ESSER, STEPHAN - Iowa State University; ERICSSON, AARON - University Of Missouri; Broadway, Paul; Sanchez, Nicole; Carroll, Jeffery; CRUZ PENN, MICHAEL - Texas Tech University; PETRY, AMY - University Of Missouri

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/26/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary: Dietary fiber plays a key role in gut health and function. Corn is the primary energy source in swine diets in the United States. However, fibrous corn-derived coproducts are often included in diets to reduce diet cost. Insoluble corn-based fibrous coproducts may upset the balance of the microbiota in the gut. A study was conducted by scientists in Lubbock, Texas and university collaborators to study the effect of corn coproducts on the gut of growing pigs. Results from this study demonstrate the need for fermentable fiber within the gut. Specifically, diets containing corn coproducts disrupted the microbial balance and mucosal barriers in the gut. Further research is needed to clarify limitations of high-fiber diets. These data will be of interest to scientists in swine nutrition and gut health, and to swine producers.

Technical Abstract: This study examined how insoluble corn-based fibrous coproducts (ICBF) compared to fiber deprivation, and altered gastrointestinal (GI) mucosal microbiota, gene expression, and intestinal morphology in growing pigs. Fifty-six gilts (26.7±2.5 kg BW), were randomly assigned to one of 7 semi-synthetic diets. Treatments included a fiber-deprived control [CTL;<1% total dietary fiber (TDF)], and 6 diets where an ICBF replaced 30% of corn starch: dehulled degermed corn (DHDG; TDF=2.4%), ground corn (COR; TDF=5.6%), corn gluten meal (CGM; TDF=6.7%), dried distillers grains (DDGS; TDF=9.5%), high protein dried distillers grains (HP; TDF=14.0%), and corn bran (BRN; TDF=17.9%). Pigs were individually housed and limit-fed 2.4 times maintenance energy needs. On day 31, pigs were necropsied for duodenum, jejunum, ileum, and colon mucosa and tissues. Microbial 16S rRNA sequencing of mucosa, tissue transcriptomics, and histological analyses were conducted in various intestinal regions. Data were analyzed using mixed models with diet as a fixed effect and linear and quadratic contrasts to assess response to insoluble dietary fiber (IDF). A negative binomial model with FDR correction were used for OTU analysis, and transcriptomics were evaluated with DESeq2 comparing ICBF sources to CTL (Q = 0.05, |log2FC| = 2). In the ileal mucosa, Shannon and Simpson diversity indices linearly increased with IDF%, while in the colon mucosa Chao1 and Shannon diversity responded quadratically (P<0.05). Among the top 100 OTUs, 60 and 86 differed in ileal and colonic mucosa, respectively (Q<0.05). Pigs fed low-ICBF diets (CTL, DHDG) had increased abundance of OTUs containing opportunistic or potentially pathogenic species (e.g., Enterobacteriaceae, Campylobacter, Streptococcus). However, moderate-to-high ICBF diets, CGM, DDGS, and BRN, enriched mucosal-associated Lactobacillus, Bifidobacterium, and Akkermansia. In the duodenum and ileum, villi height had a quadratic response to increasing IDF, while the jejunum villi height linearly decreased (P<0.05). Gene expression profiles revealed that moderate-to-high ICBF (DDGS, HP, and BRN) upregulated genes associated with cell structure and extracellular matrix (ECM) remodeling (TPPP3, MUC5AC, SERPINA1). Fiber-deprivation upregulated genes associated with ECM degradation (MMP9, MMP12), and collagen formation (COL26A1). These findings demonstrate both fiber deprivation and excessive unfermentable fiber from ICBF can disrupt mucosal microbial and host homeostasis.