December 16, 2019

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

Interpretive Summary: Effects of supplementing ruminally protected and non-protected active dried yeast on fecal bacterial community of finishing beef steers

By: Anne Wallace

Probiotics such as active dry yeast (ADY) may beneficially alter the fecal microbiomes of cattle. However, there is a need to study the effectiveness of encapsulated (or ruminally protected) versus non-ruminally protected ADY. In this ASAS-CSAS Annual Meeting and Trade Show abstract published in the December 2019 Journal of Animal Science, researchers evaluated how ADY supplementation affected the fecal microbiome of beef steers.

The animals in this study were fed one of five different diets: (1) a barley-based control diet, or a control diet with added (2) antibiotics (ANT), (3) ADY, (4) encapsulated ADY (EDY), or (5) a ADY + EDY mixture (MDY). Fecal samples were collected and analyzed in a 16S sequencer.

No changes were noted in the alpha diversity of fecal microbiomes regardless of diet. Steers fed ANT, EDY and MDY, but not ADY, however, had a significantly increased relative abundance of the Prevotella bacterial genus and a significantly decreased relative abundance of the Oscillospira bacterial genus, compared to the control group. Prevotella was noted to be the most dominant bacterial genus for beef steers regardless of diet by this study’s authors. 

Overall, these results suggest that feeding beef steers encapsulated ADY may cause a significant change in the relative abundance of fecal Prevotella, potentially comparable to antibiotics. More studies looking at the effects encapsulated probiotics (yeast, bacteria, or potentially a combination of the two) have on cattle may be useful in finding more effective ways of delivering these probiotics to cattle microbiomes.