In a natural environment, young warm-blooded animals rapidly acquire a complex microbial flora, from their mothers and the environment, soon after birth. The gut microflora make positive contributions to the nutrition of the host and is essential for the animal's resistance to infection.

A probiotic is a live microbial feed supplement, which beneficially affects the host animal by improving its intestinal microbial balance. Resulting in the maintenance or enhancement the indigenous defence mechanisms in the animal without disturbing normal physiological or biochemical functions.

Probiotics can be used cost-effectively to redress poor animal performance, when it is caused by adverse changes in the composition of the microflora. For example:

• To restore the balance of the gut microflora after bacterial infection, disease challenge or stressful event
• To prevent the balance being upset in the first place, by dosing pre-weaning, during farrowing or prior to environmental changes
• To establish or re-establish the normal flora by dosing at birth or after a course of antibiotic treatment