Levucell SB® is an active dry yeast for use as a probiotic in animal feeds. Levucell SB® contains the CNCM (Pasteur Institute) I-1079 strain of Saccharomyces cerevisiae boulardii . It is produced from a specially selected strain, has a well understood mode of action, and provides a consistently high concentration of pure viable yeast. Levucell SB® can be used in most animal feeds and is especially useful for swine, poultry, and milk replacer for young ruminant diets.s (Castex et al. 1990, Czerucka et al. 1991).