Increased intensive livestock farming and use of antibiotic growth promoters poses risks to human and animal health in terms of increasing antibiotic resistance in pathogenic micro-organisms. Live micro-organisms have been studied and used as probiotics for a long time, and as an alternative to antibiotic growth promoters in animal production. Several probiotics have been found effective in improving animal performance and preventing disease and the spread of the enteric pathogens in both monogastric and ruminant livestock industries.
With the advancement in knowledge in gastro-intestinal microbial ecology and mode of action of probiotics, the number of probiotic products available for use in animal nutrition is increasing. However, the micro-organisms used as probiotics and their efficacy are highly variable. There are many promising effects of probiotics on animal performance and health. Study about the effects of a particular microbial strain on variety of animal species, age groups, growth condition and diet types may help to identify the condition in which the probiotics could work.
The rumen has a complex microbial ecology, where polysaccharides and protein ingested by the host are degraded by rumen micro-organisms, resulting in the synthesis of microbial protein, which are used by the host as energy and protein sources. There is increasing international interest in manipulating the rumen ecosystem to increase the efficiency of the ruminal fermentation processes to improve animal productivity and reduce unwanted by-products, such as methane Yeast cultures are very beneficial in rumen . They improve rumen fermentation, nutrient digestibility, resulting to improved ruminal health and milk production in ruminants . Saccharomyces cerevisiae belongs to the yeast family and is metabolically active in the rumen and the small intestine after ingestion. The mode of action of Saccharomyces cerevisiae is, it has an ability to scavenge oxygen from the rumen making ruminal ecosystem more favorable for growth of rumen anaerobic microbes. It also enhances the ability to increase cellulolytic activity in rumen and increases the nutrient digestibility for fiber rich diets Yeast regulates the rumen pH and stops acidosis by regulating lactate producing and lactate utilizing bacteria. Saccharomyces cerevisiae induces positive effects in terms of milk yield and milk fat in ruminants by optimizing the rumen fermentation resulting to improved ruminal health and productivity and thus enhancing the dry matter digestion and absorption.
Saccharomyces cerevisiae induces positive effects in terms of milk yield and milk fat in ruminants by optimizing the rumen fermentation resulting in increased rumen bacterial numbers. Yeast also provides vitamins, especially thiamine for the growth of ruminal fungi.