Microbial dynamics in sorghum-based diets: impact of phase feeding and phytase superdosing vs. corn-based diets

This study evaluated the cecal microbiome of broilers fed sorghum- or corn-based diets with standard or superdosed phytase across different feeding phases. A total of 1500 male broiler chicks were reared for 42 days in a floor pen facility and assigned to three dietary treatments. Birds received a corn-based diet with standard phytase, a sorghum-based diet with standard phytase, or a sorghum-based diet with phytase superdosing. Cecal samples were collected at the end of the starter, grower, and finisher phases for 16S rRNA sequencing. Microbial diversity increased as birds matured, with the lowest diversity observed in the starter phase and the greatest richness in the finisher phase. Microbial community structure clustered distinctly by feeding phase, confirming that age and diet progression were the main drivers of microbiota composition. Grain type and phytase level had minimal influence on alpha or beta diversity, although sorghum inclusion was associated with shifts in specific taxa, such as increased Muribaculaceae and reduced Ruminococcaceae. Overall growth performance and microbiome profiles were similar across dietary treatments, reinforcing the potential of sorghum as an effective substitute for corn in broiler diets. The findings highlight the importance of diet phase progression in shaping gut microbial communities and demonstrate that phytase superdosing does not substantially alter microbiome dynamics under these conditions.