Abstract
The sustainability of poultry farming faces significant challenges due to rising feed costs and competition with human food sources. Dietary fibre offers a promising, cost-effective alternative due to its beneficial impact on gut health. We utilised a multi-omics approach to understand the influence of soluble inulin and insoluble cellulose dietary fibres on the composition and function of caecal microbiota in broilers. High inulin supplementation (4%) significantly altered caecal microbial composition and promoted broader microbial metabolic adaptations, indicating a strong fermentative response to this soluble fibre source. In contrast, high cellulose (4%) had a minimal impact, reflecting its limited fermentability and structural complexity. These findings provide valuable insights into how different fibre types and quantities shape gut microbial communities and their functional potential. A deeper understanding of these interactions will aid in formulating targeted dietary strategies to optimise gut health, nutrient utilisation, and overall poultry performance.