Effect of Feeding a <scp> <i>Saccharomyces cerevisiae</i> </scp> Fermentation Product on Pathogenic and Antibiotic Resistance Bacteria in Crossbred F ₁ (Luong Phuong × Ri) Broiler Chickens in the Production Systems With Low Biosecurity (Se

This study explored the effects of dietary inclusion of a Saccharomyces cerevisiae fermentation product (SCFP) on bacterial pathogens and associated antimicrobial resistance (AMR) in chickens raised in a Sector 3 production system in Vietnam. A total of 196 one-day-old F₁ (Luong Phuong × Ri) chickens were assigned to two treatments. The treatments were a standard basal diet (control) and a standard basal diet containing 1.25 kg/MT of SCFP (treatment). Fecal samples were collected three times: at 1, 42, and 85 days of age for enumeration of Escherichia coli and isolation of Salmonella. The isolates were tested for AMR and the presence of antimicrobial resistance genes (ARGs) using the disk diffusion and the PCR method. Chickens supplemented with SCFP showed significantly lower of E. coli counts (log CFU/g) compared to the control group at 85 days of age (p = 0.04). There were no differences in the level of AMR of E. coli and Salmonella between the control and treatment groups (p > 0.05). Overall, dietary supplementation of the SCFP did not affect to the frequency of Salmonella colonization and the level of AMR. However, dietary supplementation of the SCFP reduced the E. coli counts at 85 days of age.