Submitted to: Microorganisms
Publication Type: Review Article
Publication Acceptance Date: 7/29/2015
Publication Date: 8/10/2015
Citation: Broadway, P.R., Carroll, J.A., Sanchez, N.C. 2015. Yeast supplements enhance immune function and performance in food-producing livestock: A review. Microorganisms. 3(3):471-427.
Interpretive Summary: This manuscript discusses the use of yeast pro/pre biotic supplementation and its effects on the immune system and metabolism in cattle. In the current environment of food production in America, farmers and ranchers are seeking natural technologies and compounds to improve animal health and performance. Furthermore, there is increasing pressure to accomplish these goals while minimizing or eliminating the use of antibiotics. Fortunately, there are a plethora of natural alternatives to growth-promoting antibiotics that produce similar effects on performance and overall animal health and well-being. One of these alternative products is live yeast and yeast cell wall products derived from Saccharomyces cerevisiae. Yeast products are often fed to livestock as either a live yeast (direct fed microbial; DFM), as yeast cell wall, or as a combination of the two. Yeast and yeast based products enhance immune function in the presence of a stressor or an immunological insult. Not only do they enhance the immune response, yeast product supplementation also influences metabolism. These shifts in metabolism positively impact live and carcass performance, milk yield, and ultimate profitability. Overall, as can be gleamed from the literature, yeast-based products have been reported to enhance immunity and health during stressful events by acting as immunomodulators and biological response modifiers, thereby mitigating some of the negative effects associated with pathogenesis and morbidity. In part by enhancing overall gut health and altering the composition of the microbiome, these supplements also influence the metabolism of food-producing livestock. These metabolic shifts have been reported to enhance performance and growth without negatively effecting milk production or carcass characteristics. Overall these compounds represent a class of natural supplements that may partially replace the need for antibiotics and treatments due to illness. The combination of these factors has the ability to enhance animal health and well-being which may ultimately impact overall profitability.
Technical Abstract: More livestock producers are seeking natural alternatives to antibiotics and antimicrobials, and searching for supplements to enhance growth performance, and overall animal health and well-being. Some of the compounds currently being utilized and studied are live yeast and yeast-based products derived from the strain Saccharomyces cerevisiae. These products have been reported to have positive effects both directly and indirectly on the immune system and its subsequent biomarkers, thereby mitigating negative effects associated with stress and disease. These yeast-based products have also been reported to simultaneously enhance growth and performance by enhancing dry matter intake (DMI) and average daily gain (ADG) perhaps through the establishment of a healthy gastrointestinal tract. These products may be especially useful in times of potential stress such as during birth, weaning, early lactation, and during the receiving period at the feedlot. Overall, yeast supplements appear to possess the ability to improve animal health and metabolism while decreasing morbidity, thereby enhancing overall profitability of these animals.