April 16, 2020

Interpretive Summary: Feeding ruminally protected and non-protected active dried yeast to beef steers

Interpretive Summary: Fecal bacterial community of finishing beef steers fed ruminally protected and non-protected active dried yeast

By: Anne Wallace

The use of antimicrobials to promote the growth of feedlot animals is restricted or banned in many countries. The drive to move away from antimicrobials is mainly due to the emergence of antibiotic resistance. Therefore, alternatives are needed. One such possibility is probiotic bacteria or yeasts – such as Saccharomyces cerevisiae – an active dry yeast (ADY). Probiotic microorganisms attenuate pathogenic organisms while simultaneously promoting health, without the unwanted negative impacts of antimicrobial growth promoters.

The authors of this April 2020 Journal of Animal Science study hypothesized that ADY would beneficially alter the hindgut microbiota of beef steers. Steers were fed a high-grain diet supplemented with either antibiotics (ANT), ruminally protected ADY (EDY), non-protected ADY (ADY), a mix of EDY and ADY, or a control diet (not given any ADY, EDY or ANT). Fecal microbial differences were analyzed via 16S genetic sequencing for each group and compared to the control group.

There were no significant differences in fecal microbial diversity for any of the five groups. However, the relative abundance of the genus Prevotella was increased in the ANT, EDY and MDY groups, compared to the control group. In the ANT, EDY and MDY groups, the relative abundance of the phylum Bacteroidetes was increased, while the phylum Firmicutes and genus Oscillospira were decreased, compared to the control group.

Overall, the results of this study support the researchers’ hypothesis that supplementation with ruminally protected ADY alters the hindgut microbiota of beef steers. Considering the genus Prevotella is associated with benefits to gut health and was increased in the EDY and MDY groups in this study, encapsulated ADY may have the potential to benefit steer hindgut health. However, more in-depth studies to explore what specific benefits the supplementation of encapsulated ADY may entail are needed.