Prospect of yeast probiotic inclusion enhances livestock feeds utilization and performance: an overview

An important aspect of live yeast (Saccharomyces cerevisiae) inclusion in the diets of ruminants is improved animal productivity. Inclusion of yeasts in ruminant diets may alter rumen microbes and their metabolites and promote a favorable intestinal microflora by increasing the population of beneficial microorganisms. Beneficial microbes compete for nutrients and attachment sites with pathogens, thereby reducing the growth of harmful microbes in the rumen. Yeasts enhance growth and average daily weight gain of animals by improving nutrients digestion and absorption. Probiotics can alter the fatty acid composition of meat and milk, and it is common knowledge that a lower fatty acid profile may directly confer health benefits to consumers by reducing harmful cholesterol levels in animal products and thus favorable to human nutrition. Furthermore, yeast probiotics have been shown to enhance immunity by inducing an immunomodulatory effect on the animal in addition to their ability to lower cholesterol, adhesion properties of the intestinal mucosa, and colonial resistance to strengthen gut integrity. This review highlights that yeast probiotics play a role in the ruminal microbial population dynamics, cholesterol-lowering ability and immunostimulatory potentials, yeast adhesion properties, and colonial resistance. Additional benefits include a healthy gut with concomitant increase in animal productivity, nutrient digestion, and absorption and general animal welfare. Overall, yeast probiotics appear to be a viable alternative to the use of antibiotics to improve animal welfare.