Saccharomyces boulardii RC009 as an alternative to prophylactic antibiotics: effects on broiler chickens, performance, and gut microbiome

Abstract

This study evaluates the effects of supplementing broiler chicken feed with the probiotic Saccharomyces cerevisiae var. boulardii RC009 as a sustainable alternative to prophylactic antibiotics. The focus was on productive performance, gut microbiome composition, and the time to reach slaughter weight. The trial involved 77,200 one-day-old Cobb-500 broiler chickens housed on 5 floor pens. Two groups were compared: Control (Basal Diet + antibiotics) and Probiotic (Basal Diet + S. boulardii RC009, without antibiotics). The probiotic was administered from day 0 until the birds reached 3 kg. The Probiotic group showed notable improvements: males reached 10.97% higher slaughter weight and achieved market size two days earlier than controls. Histomorphological analysis indicated preserved intestinal health, with no significant differences between groups. 16S rDNA sequencing revealed that the probiotic significantly altered the gut microbiota. Although overall microbial diversity slightly decreased, there was a marked enrichment of methanogenic Archaea, particularly Methanobrevibacter and other Methanobacteriales, alongside a reduction in dominant bacterial families such as Ruminococcaceae and Lachnospiraceae. These findings suggest that supplementation with S. boulardii RC009 improved broiler performance by increasing slaughter weight and reducing time to market. The rise in methanogenic Archaea suggests enhanced redox balance and potential increases in ShortChain Fatty Acid (SCFA) production, contributing to better digestibility and antiinflammatory effects. These results support S. boulardii RC009 as a viable, sustainable alternative to antibiotic growth promoters in poultry farming.