The increase in livestock production systems has resulted in serious environmental impact
due to emission of greenhouse gases and the possibility of transfer of zoonotic diseases
to humans. Initially, antimicrobial drugs used as feed additives to overcome these challenges
led to the emergence of resistant pathogens and have now been banned. The current
trend in animal nutrition is to provide feed that meets nutritional needs, maintains healthy
status and lowers the possibilities of infection. Probiotics have been described by many
researchers to be an effective natural strategy towards improving an animal’s health and
performance. Probiotics are live microorganisms which confer health benefits on the host
by modifying the intestinal microflora and probiotic yeasts have been used for decades as
microbial feed additives. This review focuses on the positive influence of yeast supplementation
in animal feed and some of the mechanisms by which these benefits are achieved
have also been discussed.