Probiotics are live microorganisms that may confer a health benefit on the host. They have been studied in human and veterinary patients with inflammatory bowel disease; diarrhea from such organisms as Clostridium, Salmonella, and Campylobacter; allergies, including atopic dermatitis; recurrent urinary tract disease; chronic renal disease; and pancreatitis. Some commercial probiotic products have quality control issues, such as viability and inclusion of bacterial species not listed on the label. It is extremely difficult to maintain live organisms during processing and storage of pet food, and the value of nonviable probiotic bacteria is debatable. Of 19 "holistic" dog and cat commercial foods claiming to contain probiotics, 12 did not contain live organisms.  Only 53% contained at least one of the listed species, and none of the 19 contained all of the probiotics listed on the labels.

COMMENTARY: More research into potential benefits of probiotics and the practicality of their use is needed. Quality control appears to be a big issue. Some probiotic supplements may not contain beneficial levels of viable organisms, and ensuring the quality and quantity of probiotics incorporated into pet food is even more difficult. A different, more practical approach that warrants further research is the use of prebiotics, which are polysaccharides that support growth of certain beneficial bacteria and result in production of nourishing short-chain fatty acids in the colon. -- Patricia Thomblison, DVM, MS

Probiotics in veterinary practice. Wynn SG. NAVC PROC 2008, p 854.