Changing consumer preferences, combined with regulatory shifts, have altered the landscape poultry producers use to evaluate their feed additive choices. Prebiotics and probiotics are increasingly popular choices, but the difference between the two is not always fully understood.
While complementary to each other, prebiotics and probiotics are not necessarily interchangeable in a diet, nor are they the same in how they affect gut microbes. They feature different modes of action and stem from different origins.
They may be used in animal diets independently or in combination to help producers accomplish the desired outcomes of enhanced animal health and productivity.
Prebiotics
Prebiotics act as a food source for the good bacteria that are already living in the gastrointestinal (GI) tract and have been shown to support animal health and performance.
More formally, a prebiotic is a specialized, non-digestible carbohydrate that beneficially sustains the good bacteria already in the GI tract. A prebiotic is not a microorganism. It is a sort of nourishment source for existing bacteria, allowing the existing typical colony within an animal’s gut to grow naturally and reproduce.2
Prebiotics may be obtained from several sources, including particular yeast cell walls such as Saccharomyces cerevisiae.
Prebiotics are complex sugars (usually oligomers), but not all sugars are prebiotics. Many sugars are digestible by the animal and are used as an energy source.

Probiotics
The word “probiotic” comes from the Greek words “pro” and “biotic,” meaning “for life.”
Probiotics have sometimes been referred to as “direct-fed microbial.” Targeted microbial solutions is a more descriptive term. These are proprietary strains of Bacillus selected to combat the specific challenges in a farm’s Microbial Terroir™—which includes the environment, soil, animals, and weather in a particular farm location.
These good strains of bacteria help combat harmful pathogens that are impacting animals’ performance and are a live microbial feed additive that beneficially affects the host animal by improving its intestinal balance.
In short, probiotics are the “good” bacteria that live in the animal’s GI tract. They work by competitive exclusion—that means when adequate populations of probiotic bacteria are present, they reduce pathogenic bacteria’s ability to get out of control and overwhelm the host. , they crowd pathogens out. They also work by explicitly inhibiting pathogenic growth.