A Prevotella-Rich Gut Microbiota and Microbial CAZymes Are Associated with Half-Diving Length in Ducks

The gut microbiota is closely associated with host growth by nutritional metabolism and immune homeostasis. Half-diving length, a key indicator of duck development and production efficiency, correlates with economic traits like body weight and slaughter yield, yet its link to gut microbiota remains unclear. This study combined metagenomic and metabolomic analyses to explore the association between gut microbiota and duck half-diving length. We found distinct microbial communities between ducks with high (H) and low (L) half-diving lengths: the H group had more carbohydrate-active enzymes (CAZymes) genes (p < 0.05), especially glycoside hydrolases (GHs), and was enriched in MAG3173 (Prevotella sp000431975), which features complete carbohydrate and amino acid metabolic pathways and key CAZymes. Metabolomics revealed slightly higher short-chain fatty acids (SCFAs) levels in the H group, but glycerophospholipids, particularly phosphatidylinositol (PI), were significantly upregulated (p < 0.05). The Prevotella-rich microbial structure in the H group is potentially linked to enhanced polysaccharide degradation capacity and altered SCFAs abundance. This metabolic shift may be associated with host energy supply and lipid metabolic profiles, thereby influencing duck growth. Collectively, this study found significant correlations between duck half-diving length and gut microbial composition, functional capacity, and intestinal metabolic signatures. The study proposes the hypothesis of a potential Prevotella-CAZymes-glycerophospholipid metabolism axis, which might offer a theoretical reference and candidate microbial targets for understanding the microbe–phenotype association in waterfowl.