ABSTRACT This study investigated the efficacy of various dietary fiber sources and combinations in mitigating subclinical enteric infection in broilers. Using a randomized complete block design, 2,160 d-old YP x Ross 708 male broilers were assigned to eight treatments. These included an unchallenged control and a challenged control, followed by six dietary treatments applied to challenged broilers. The dietary treatments consisted of fiber supplementation with oat hulls ( OH ) or soy hulls ( SH ), either alone or in combination with wheat middlings ( WM ) or sugar beet pulp ( SBP ). Birds were challenged with Eimeria spp. followed by Clostridium perfringens , and a multi-omics approach was employed to analyze jejunal histopathology, microbiome, and host mucosal transcriptome. While the enteric challenge induced significant histopathological changes, fiber combinations including OH-WM and OH-SBP significantly ( P < 0.05) reduced cumulative pathology scores. The challenge caused a shift toward Lactobacillus crispatus dominance in the microbiome. Each fiber source altered the microbiome distinctively: OH increased Romboutsia sp., OH-SBP enriched beneficial Limosilactobacillus spp., and SH combinations enhanced butyrate-producing Dysosmobacter welbionis . Transcriptome analysis revealed that fiber supplementation suppressed inflammatory pathways while upregulating cell cycle progression and DNA repair pathways. Integration of bacteriome with host gene expression data revealed coordinated associations, including a link between Glutamicibacter protophormiae, Spirosoma, Eggerthella , and Blautia through host genes APOB, DSEL, and ENPP7, indicating a correlation of fiber-degrading bacteria with host lipid metabolism and extracellular matrix remodeling. These findings suggest that combining insoluble and soluble fibers may create a more resilient gut environment against enteric challenges through complementary mechanisms, with OH based combinations notably exhibiting reduced pathology, stronger anti-inflammatory response and suppression of opportunistic species.
Tabish et al. (2026) studied this question.