Probiotics are supplements of beneficial bacteria given to re-establish the normal bacterial flora in the bird's digestive tract. They are often given after antibiotic therapy or severe gastrointestinal disturbances. The most effective means of administering probiotics is through the use of a liquid or powdered form mixed into the drinking water. Probiotics help by increasing the population of good bacteria in the intestines, to help fight off the bad bacteria.
Lactobacillus and bifidobacterium are the specific types of 'good' bacteria used in probiotics.
Bifidobacteria: These are Gram-positive bacterial organisms that by consuming oligosaccharides, produce lactic acid, acetic acid, ethanol, and formic acid. B. longum has shown to be beneficial for inhibiting harmful campylobacter bacteria in chickens.
Lactobacilli: These are a type of beneficial bacterial that are collectively referred to as lactic acid bacteria, which, like Bifidobacteria, metabolize oligosaccharides to produce lactic acid as the primary end product. L. reuteri and L. fermentum have shown to be of benefit to chickens.