PSIX-11 The Effect of Probiotic Supplementation on the Alpha Diversity and Proteobacteria Ratio in South African Feedlot Cattle in the Finisher Phase

Abstract Probiotics are known to stabilize the microbiome especially in monogastric animals. Limited information is available on potential effect rumen microbiome. Feedlot cattle fed high concentrate diets which may result subclinical and clinical acidosis due dysbiosis. This can negatively affect production lead morbidities death. The alpha diversity of a population ratio Proteobacteria towards Firmicutes Bacteroidetes have been indicate aim this study was investigate probiotics feedlot during finisher phase. Thirty-six Bonsmara bulls were randomly divided into three groups for 120 days; basal diet commonly South African feedlots (CTR: control), supplemented with monensin (30 mg/animal/day; MON) or Bacillus-based probiotic (B. licheniformis B. subtilis; Bovacillus, Chr. Hansen A/S at 2.75 g/animal/day; BOV). Four animals from each selected content collection phase using stomach tube. After DNA extraction completed, 16S rRNA sequencing (V3-V4) performed. Alpha (Shannon) relative abundance phyla determined phyloseq significance (p< 0.05) Kruskal-Wallis test. In total, 41 300 ASVs 10 identified. BOV had significantly greater (p=0.023) compared CTR numerically MON. than expected all groups. However, less (p=0.028) results that supplementation has by increasing decreasing thereby preventing