Prebiotics versus probiotics: What’s the difference? (Poultry Specialist)

(Editor’s note: Jennifer Timmons is an associate professor with the University of Maryland Eastern Shore.)

Regulations have been introduced to reduce the use of antibiotics in animal feed due to fear of the development of multi-drug resistant bacteria strains finding their way into human clinics.
More than 50 percent of the broiler chickens raised in the United States are produced in “no antibiotics ever” (NAE) programs.
This means that antibiotics are not used during the entire production period (hatchery, feedmill, and grow-out).
With this limited or no use of antibiotics during the production process, alternative antimicrobials to reduce pathogens are needed.
Two alternatives that are available to use to promote overall gut health in broiler chickens and reduce pathogens are prebiotics and probiotics.
Prebiotics and probiotics have been utilized in animal production to help maintain a healthy balance of bacteria in the gastrointestinal tract through competitive exclusion.
It is common to see these products listed as ingredients in pet foods, and chicken and livestock feed.
We even see these products sold to promote human health. 
So what is the difference between these two products and how do they work? The World Health Organization working group with the Food and Agriculture Organization of the United Nations (FAO) defines probiotics as “live microorganisms which when administered in adequate amount confer health benefits in the host.” Think yogurt.
Some of these probiotic bacteria are Lactobacillus and Bifidobacterim species.
Probiotics work by competitive exclusion in the intestinal tract of the animal.
This means there is competition of attachment sites in the gut.
The probiotic bacteria attach to sites along the intestinal mucosa which prohibits or blocks the attachment of pathogenic bacteria.
This reduces the ability of pathogenic bacteria to get out of control and possibly cause harm to the animal.
Prebiotics are non-digestible feed ingredients that benefit the host by stimulating the growth of beneficial bacteria in the gut. The most common prebiotics are non-digestible carbohydrates.
Prebiotics act one of two ways: 1. they supply nutrients to beneficial bacteria or 2. they provide binding sites for pathogenic bacteria to attach to instead of attaching to the intestinal tract of the animal.
Since the prebiotic is non-digestible, the bacteria that are attached to it will be excreted from the animal along with other undigested food.
This reduces the growth and the incidence of infection from the pathogenic bacteria.
Prebiotics and probiotics can be used separately in broiler chicken diets or in combination to improve broiler health and performance.
There are many considerations when it comes to feeding prebiotics and probiotics since there are several products available to use.
It has been reported by several researchers that the use of probiotics and prebiotics can improve the health and performance of broiler chickens.
A recent study not only reported improvements in weight gain and feed conversion ratio of 35 day old broiler chickens when they were fed a probiotic and prebiotic, it was also reported that the immunity of the birds was improved.
The researchers reported that the antibody titer for infectious bursal disease was improved in the broiler chickens that were fed the pre- and probiotic treatments compared to the antibody titer measured in broiler chickens fed the control diet.
In addition to feeding these products to broiler chickens, studies have also been conducted evaluating the effect of administering probiotics in ovo in broiler chicks on hatchability and performance.
The researchers reported that there was no effect on hatchability. Post-hatch, birds were challenged with coccidia species and birds that were administered the probiotic in ovo had a higher body weight compared to the birds that were not administered the probiotic in ovo.
As the industry continuously seeks out alternatives to antibiotics, prebiotics and probiotics have a lot of potential to benefit poultry health and performance.
However, the cost of these products should be considered against their potential benefits to improve broiler health and performance.
There are several probiotics and prebiotics products available on the market. An evaluation of the efficacy of these products under current field conditions would help determine if the use of these products would be economically beneficial for wide spread use.